A182944 -id:A182944 - cp's OEIS frontend

A182945 Array of prime powers p^j, as transpose of A182944.

2, 3, 4, 5, 9, 8, 7, 25, 27, 16, 11, 49, 125, 81, 32, 13, 121, 343, 625, 243, 64, 17, 169, 1331, 2401, 3125, 729, 128, 19, 289, 2197, 14641, 16807, 15625, 2187, 256, 23, 361, 4913, 28561, 161051, 117649, 78125, 6561, 512, 29, 529, 6859, 83521, 371293, 1771561, 823543, 390625, 19683, 1024

Offset: 1

Clark Kimberling, Dec 14 2010

The monotonic ordering of this sequence, with 1 prefixed, is A000961.

The joint-rank array of this sequence is A182869.

			Northwest corner:
   2    3     5     7
   4    9    25    49
   8   27   125   343
  16   81   625  2401

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A000961, A182944, A000040 (row 1), A001248 (row 2), A030078 (row 3).
Antidiagonal products give A006939.
Cf. A319075 (extends the array with 0th powers).

[NthPrime(n-i)^i: i in [1..n-1], n in [2..15]]; // Vincenzo Librandi, Jul 28 2015

seq(seq(ithprime(n-i)^i,i=1..n-1),n=2..20); # Robert Israel, Jul 27 2015

width=9;Table[Table[Prime[n]^j,{n,1,width},{j,1,width}]]; Flatten[Table[Table[%[[z-k+1]][[k]],{k,1,z}],{z,1,width}]]

A062457 a(n) = prime(n)^n.

Original entry on oeis.org

2, 9, 125, 2401, 161051, 4826809, 410338673, 16983563041, 1801152661463, 420707233300201, 25408476896404831, 6582952005840035281, 925103102315013629321, 73885357344138503765449, 12063348350820368238715343, 3876269050118516845397872321

Offset: 1

Labos Elemer, Jul 09 2001

Heinz numbers of square integer partitions, where the Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). - Gus Wiseman, Apr 14 2018
Main diagonal of A182944. - Omar E. Pol, Sep 12 2018
Second diagonal of A319075. - Omar E. Pol, Sep 13 2018

T. D. Noe, Table of n, a(n) for n = 1..100

Cf. A000040, A000312, A000720, A000961, A001222, A051674, A062006, A076146, A093358, A201614, A275024, A302242, A302493, A302498, A319075.

[NthPrime(n)^n : n in [1..20]]; // Wesley Ivan Hurt, Jan 18 2016

A062457:=n->ithprime(n)^n: seq(A062457(n), n=1..20); # Wesley Ivan Hurt, Jan 18 2016

Table[Prime[n]^n, {n,20}] (* Harvey P. Dale, Jun 22 2011 *)

a(n) = prime(n)^n; \\ Harry J. Smith, Aug 07 2009

a(n) = A062006(n) - 1. - Wesley Ivan Hurt, Jan 18 2016
From Amiram Eldar, Nov 16 2020: (Start)
Sum_{n>=1} 1/a(n) = A093358.
Sum_{n>=1} (-1)^(n+1)/a(n) = A201614. (End)

A329332 Table of powers of squarefree numbers, powers of A019565(n) in increasing order in row n. Square array A(n,k) n >= 0, k >= 0 read by descending antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 4, 3, 1, 1, 8, 9, 6, 1, 1, 16, 27, 36, 5, 1, 1, 32, 81, 216, 25, 10, 1, 1, 64, 243, 1296, 125, 100, 15, 1, 1, 128, 729, 7776, 625, 1000, 225, 30, 1, 1, 256, 2187, 46656, 3125, 10000, 3375, 900, 7, 1, 1, 512, 6561, 279936, 15625, 100000, 50625, 27000, 49, 14

Offset: 0

Peter Munn, Nov 10 2019

The A019565 row order gives the table neat relationships with A003961, A003987, A059897, A225546, A319075 and A329050. See the formula section.

Transposition of this table, that is reflection about its main diagonal, has subtle symmetries. For example, consider the unique factorization of a number into powers of distinct primes. This can be restated as factorization into numbers from rows 2^n (n >= 0) with no more than one from each row. Reflecting about the main diagonal, this factorization becomes factorization (of a related number) into numbers from columns 2^k (k >= 0) with no more than one from each column. This is also unique and is factorization into powers of squarefree numbers with distinct exponents that are powers of two. See the example section.

			Square array A(n,k) begins:
n\k |  0   1     2      3        4          5           6             7
----+------------------------------------------------------------------
   0|  1   1     1      1        1          1           1             1
   1|  1   2     4      8       16         32          64           128
   2|  1   3     9     27       81        243         729          2187
   3|  1   6    36    216     1296       7776       46656        279936
   4|  1   5    25    125      625       3125       15625         78125
   5|  1  10   100   1000    10000     100000     1000000      10000000
   6|  1  15   225   3375    50625     759375    11390625     170859375
   7|  1  30   900  27000   810000   24300000   729000000   21870000000
   8|  1   7    49    343     2401      16807      117649        823543
   9|  1  14   196   2744    38416     537824     7529536     105413504
  10|  1  21   441   9261   194481    4084101    85766121    1801088541
  11|  1  42  1764  74088  3111696  130691232  5489031744  230539333248
  12|  1  35  1225  42875  1500625   52521875  1838265625   64339296875
Reflection of factorization about the main diagonal: (Start)
The canonical (prime power) factorization of 864 is 2^5 * 3^3 = 32 * 27. Reflecting the factors about the main diagonal of the table gives us 10 * 36 = 10^1 * 6^2 = 360. This is the unique factorization of 360 into powers of squarefree numbers with distinct exponents that are powers of two.
Reflection about the main diagonal is given by the self-inverse function A225546(.). Clearly, all positive integers are in the domain of A225546, whether or not they appear in the table. It is valid to start from 360, observe that A225546(360) = 864, then use 864 to derive 360's factorization into appropriate powers of squarefree numbers as above.
(End)

The range of values is A072774.
Rows (abbreviated list): A000079(1), A000244(2), A000400(3), A000351(4), A011557(5), A001024(6), A009974(7), A000420(8), A001023(9), A009965(10), A001020(16), A001022(32), A001026(64).
A019565 is column 1, A334110 is column 2, and columns that are sorted in increasing order (some without the 1) are: A005117(1), A062503(2), A062838(3), A113849(4), A113850(5), A113851(6), A113852(7).
Other subtables: A182944, A319075, A329050.
Re-ordered subtable of A297845, A306697, A329329.
A000290, A003961, A003987, A059897 and A225546 are used to express relationships between terms of this sequence.
Cf. A285322.

A(n,k) = A019565(n)^k.
A(k,n) = A225546(A(n,k)).
A(n,2k) = A000290(A(n,k)) = A(n,k)^2.
A(2n,k) = A003961(A(n,k)).
A(n,2k+1) = A(n,2k) * A(n,1).
A(2n+1,k) = A(2n,k) * A(1,k).
A(A003987(n,m), k) = A059897(A(n,k), A(m,k)).
A(n, A003987(m,k)) = A059897(A(n,m), A(n,k)).
A(2^n,k) = A319075(k,n+1).
A(2^n, 2^k) = A329050(n,k).
A(n,k) = A297845(A(n,1), A(1,k)) = A306697(A(n,1), A(1,k)), = A329329(A(n,1), A(1,k)).
Sum_{n>=0} 1/A(n,k) = zeta(k)/zeta(2*k), for k >= 2. - Amiram Eldar, Dec 03 2022

A329050 Square array A(n,k) = prime(n+1)^(2^k), read by descending antidiagonals (0,0), (0,1), (1,0), (0,2), (1,1), (2,0), ...; Fermi-Dirac primes (A050376) in matrix form, sorted into rows by their prime divisor.

Original entry on oeis.org

2, 4, 3, 16, 9, 5, 256, 81, 25, 7, 65536, 6561, 625, 49, 11, 4294967296, 43046721, 390625, 2401, 121, 13, 18446744073709551616, 1853020188851841, 152587890625, 5764801, 14641, 169, 17, 340282366920938463463374607431768211456, 3433683820292512484657849089281, 23283064365386962890625, 33232930569601, 214358881, 28561, 289, 19

Offset: 0

Antti Karttunen and Peter Munn, Nov 02 2019

This sequence is a permutation of A050376, so every positive integer is the product of a unique subset, S_factors, of its terms. If we restrict S_factors to be chosen from a subset, S_0, consisting of numbers from specified rows and/or columns of this array, there are notable sequences among those that may be generated. See the examples. Other notable sequences can be generated if we restrict the intersection of S_factors with specific rows/columns to have even cardinality. In any of the foregoing cases, the numbers in the resulting sequence form a group under the binary operation A059897(.,.).
Shares with array A246278 the property that columns grow downward by iterating A003961, and indeed, this array can be obtained from A246278 by selecting its columns 1, 2, 8, 128, ..., 2^((2^k)-1), for k >= 0.
A(n,k) is the image of the lattice point with coordinates X=n and Y=k under the inverse of the bijection f defined in the first comment of A306697. This geometric relationship can be used to construct an isomorphism from the polynomial ring GF(2)[x,y] to a ring over the positive integers, using methods similar to those for constructing A297845 and A306697. See A329329, the ring's multiplicative operator, for details.

			The top left 5 X 5 corner of the array:
  n\k |   0     1       2           3                   4
  ----+-------------------------------------------------------
   0  |   2,    4,     16,        256,              65536, ...
   1  |   3,    9,     81,       6561,           43046721, ...
   2  |   5,   25,    625,     390625,       152587890625, ...
   3  |   7,   49,   2401,    5764801,     33232930569601, ...
   4  |  11,  121,  14641,  214358881,  45949729863572161, ...
Column 0 continues as a list of primes, column 1 as a list of their squares, column 2 as a list of their 4th powers, and so on.
Every nonnegative power of 2 (A000079) is a product of a unique subset of numbers from row 0; every squarefree number (A005117) is a product of a unique subset of numbers from column 0. Likewise other rows and columns generate the sets of numbers from sequences:
Row 1:                 A000244 Powers of 3.
Column 1:              A062503 Squares of squarefree numbers.
Row 2:                 A000351 Powers of 5.
Column 2:              A113849 4th powers of squarefree numbers.
Union of rows 0 and 1:     A003586 3-smooth numbers.
Union of columns 0 and 1:  A046100 Biquadratefree numbers.
Union of row 0 / column 0: A122132 Oddly squarefree numbers.
Row 0 excluding column 0:  A000302 Powers of 4.
Column 0 excluding row 0:  A056911 Squarefree odd numbers.
All rows except 0:         A005408 Odd numbers.
All columns except 0:      A000290\{0} Positive squares.
All rows except 1:         A001651 Numbers not divisible by 3.
All columns except 1:      A252895 (have odd number of square divisors).
If, instead of restrictions on choosing individual factors of the product, we restrict the product to be of an even number of terms from each row of the array, we get A262675. The equivalent restriction applied to columns gives us A268390; applied only to column 0, we get A028260 (product of an even number of primes).

Antti Karttunen, Table of n, a(n) for n = 0..77; the first 12 antidiagonals of array
Wikipedia, Polynomial ring

Transpose: A329049.
Permutation of A050376.
Rows 1-4: A001146, A011764, A176594, A165425 (after the two initial terms).
Columns 1-5: A000040, A001248, A030514, A179645, A030635.
Antidiagonal products: A191555.
Subtable of A182944, A242378, A246278, A329332.
A000290, A003961, A225546 are used to express relationship between terms of this sequence.
Related binary operations: A059897, A306697, A329329.
See also the table in the example section.

Table[Prime[#]^(2^k) &[m - k + 1], {m, 0, 7}, {k, m, 0, -1}] // Flatten (* Michael De Vlieger, Dec 28 2019 *)

up_to = 105;
A329050sq(n,k) = (prime(1+n)^(2^k));
A329050list(up_to) = { my(v = vector(up_to), i=0); for(a=0, oo, for(col=0, a, i++; if(i > up_to, return(v)); v[i] = A329050sq(col, a-col))); (v); };
v329050 = A329050list(up_to);
A329050(n) = v329050[1+n];
for(n=0,up_to-1,print1(A329050(n),", ")); \\ Antti Karttunen, Nov 06 2019

A(0,k) = 2^(2^k), and for n > 0, A(n,k) = A003961(A(n-1,k)).
A(n,k) = A182944(n+1,2^k).
A(n,k) = A329332(2^n,2^k).
A(k,n) = A225546(A(n,k)).
A(n,k+1) = A000290(A(n,k)) = A(n,k)^2.

Example annotated for clarity by Peter Munn, Feb 12 2020

A284457 Square array whose rows list numbers with the same squarefree kernel (A007947): Transpose of A284311.

Original entry on oeis.org

2, 4, 3, 8, 9, 5, 16, 27, 25, 6, 32, 81, 125, 12, 7, 64, 243, 625, 18, 49, 10, 128, 729, 3125, 24, 343, 20, 11, 256, 2187, 15625, 36, 2401, 40, 121, 13, 512, 6561, 78125, 48, 16807, 50, 1331, 169, 14, 1024, 19683, 390625, 54, 117649, 80, 14641, 2197, 28, 15

Offset: 1

Bob Selcoe, Mar 27 2017

The first column contains the squarefree numbers A005117; each row lists all numbers having the same prime divisors. If T[m,1] is prime then the row contains the powers of that prime. Yields A182944 if only these rows with prime powers (A000961) are kept. - M. F. Hasler, Mar 27 2017

See A284311 for further details.

			Array starts:
    2    4     8     16      32      64      128
    3    9    27     81     243     729     2187
    5   25   125    625    3125   15625    78125
    6   12    18     24      36      48       54
    7   49   343   2401   16807  117649   823543
   10   20    40     50      80     100      160
   ...
Row 6 is: T[1,6] = 2*5; T[2,6] = 2^2*5; T[3,6] = 2^3*5; T[4,6] = 2*5^2; T[5,6] = 2^4*5, etc.

Alois P. Heinz, Antidiagonals n = 1..141, flattened

Cf. A284311, A005117, A007947, A065642, A182944.

Cf. A008479 (index of the column where n is located), A285329 (of the row).

f[n_, k_: 1] := Block[{c = 0, sgn = Sign[k], sf}, sf = n + sgn; While[c < Abs@ k, While[! SquareFreeQ@ sf, If[sgn < 0, sf--, sf++]]; If[sgn < 0, sf--, sf++]; c++]; sf + If[sgn < 0, 1, -1]] (* after Robert G. Wilson v at A005117 *); T[n_, k_] := T[n, k] = Which[And[n == 1, k == 1], 2, k == 1, f@ T[n - 1, k], PrimeQ@ T[n, 1], T[n, 1]^k, True, Module[{j = T[n, k - 1]/T[n, 1] + 1}, While[PowerMod[T[n, 1], j, j] != 0, j++]; j T[n, 1]]]; Table[T[n - k + 1, k], {n, 10}, {k, n, 1, -1}] // Flatten

A284457(m,n)={for(a=2,m^2+1,(core(a)!=a||m--)&&next;m=factor(a)[,1]; for(k=1,9e9,factor(k*a)[,1]==m&&!n--&&return(k*a)))} \\ M. F. Hasler, Mar 27 2017

(define (A284457 n) (A284311bi (A004736 n) (A002260 n))) ;; For A284311bi, see A284311. - Antti Karttunen, Apr 17 2017

From Antti Karttunen, Apr 17 2017: (Start)
A(n,1) = A005117(1+n), A(n,k) = A065642(A(n,k-1)). [A "dispersion" of A065642.]
A(A285329(n), A008479(n)) = n for all n >= 2.(End)

Edited by M. F. Hasler, Mar 27 2017

A319075 Square array T(n,k) read by antidiagonal upwards in which row n lists the n-th powers of primes, hence column k lists the powers of the k-th prime, n >= 0, k >= 1.

Original entry on oeis.org

1, 2, 1, 4, 3, 1, 8, 9, 5, 1, 16, 27, 25, 7, 1, 32, 81, 125, 49, 11, 1, 64, 243, 625, 343, 121, 13, 1, 128, 729, 3125, 2401, 1331, 169, 17, 1, 256, 2187, 15625, 16807, 14641, 2197, 289, 19, 1, 512, 6561, 78125, 117649, 161051, 28561, 4913, 361, 23, 1, 1024, 19683, 390625, 823543, 1771561, 371293

Offset: 0

Omar E. Pol, Sep 09 2018

If n = p - 1 where p is prime, then row n lists the numbers with p divisors.

The partial sums of column k give the column k of A319076.

			The corner of the square array is as follows:
         A000079 A000244 A000351  A000420    A001020    A001022     A001026
A000012        1,      1,      1,       1,         1,         1,          1, ...
A000040        2,      3,      5,       7,        11,        13,         17, ...
A001248        4,      9,     25,      49,       121,       169,        289, ...
A030078        8,     27,    125,     343,      1331,      2197,       4913, ...
A030514       16,     81,    625,    2401,     14641,     28561,      83521, ...
A050997       32,    243,   3125,   16807,    161051,    371293,    1419857, ...
A030516       64,    729,  15625,  117649,   1771561,   4826809,   24137569, ...
A092759      128,   2187,  78125,  823543,  19487171,  62748517,  410338673, ...
A179645      256,   6561, 390625, 5764801, 214358881, 815730721, 6975757441, ...
...

Rows 0-13: A000012, A000040, A001248, A030078, A030514, A050997, A030516, A092759, A179645, A179665, A030629, A079395, A030631, A138031.
Other rows n: A030635 (n=16), A030637 (n=18), A137486 (n=22), A137492 (n=28), A139571 (n=30), A139572 (n=36), A139573 (n=40), A139574 (n=42), A139575 (n=46), A173533 (n=52), A183062 (n=58), A183085 (n=60), A261700 (n=100).
Columns 1-15: A000079, A000244, A000351, A000420, A001020, A001022, A001026, A001029, A009967, A009973, A009975, A009981, A009985, A009987, A009991.
Main diagonal gives A093360.
Second diagonal gives A062457.
Third diagonal gives A197987.
Removing the 1's we have A182944/ A182945.
Cf. A006093, A319074, A319076.

PARI
```
T(n, k) = prime(k)^n;
```

T(n,k) = A000040(k)^n, n >= 0, k >= 1.

A332979 Largest integer m satisfying Omega(m) + pi(gpf(m)) - [m<>1] = n.

Original entry on oeis.org

1, 2, 4, 9, 27, 125, 625, 3125, 16807, 161051, 1771561, 19487171, 214358881, 2357947691, 25937424601, 285311670611, 3138428376721, 34522712143931, 582622237229761, 9904578032905937, 168377826559400929, 2862423051509815793, 48661191875666868481

Offset: 0

Alois P. Heinz, Mar 04 2020

nonn

From Michael De Vlieger, Aug 22 2022: (Start)
Subset of A000961.
Maxima of row n of A005940.
Maxima of row n of A182944 and row n of A182945. (End)

Alois P. Heinz, Table of n, a(n) for n = 0..461
Michael De Vlieger, Concise table of n, a(n) for n = 1..10000, where a(n) = prime(k)^e written as "pk^e". (a(0) = 1 is presented as "p1^0" to avoid reconversion errors in some CAS associated with "prime(0)".)
Michael De Vlieger, Annotated plot of a(n) = prime(k)^e at (x,y) = (e,k) for n = 1..64, showing the first and last terms divisible by prime(k) in red, singleton powers of prime(k) in green, otherwise blue.
Michael De Vlieger, Plot of a(n) = prime(k)^e at (x,y) = (e,k) for n = 1..10000.
Michael De Vlieger, Fan style binary tree showing row m = 2..15 of A005940 in concentric semicircles. Terms in light blue appear in row m-1 of A182944, highlighting a(m-1) in red.
Michael De Vlieger, Fan style binary tree showing row m = 2..15 of A005940 in concentric semicircles. We apply a color function with dark blue the minimum and greens the largest values to show the magnitude of terms in row m compared to 2^(m-1). The row maximum a(m-1) appears in red.
Wikipedia, Iverson bracket

Cf. A000720 (pi), A001222 (Omega), A006530 (GPF), A011782, A060576 ([n<>1]), A061395 (pi(gpf(n))), A332977.

b:= proc(n, i) option remember; `if`(n=0, 1, max(seq(b(n-
     `if`(i=0, j, 1), j)*ithprime(j), j=1..`if`(i=0, n, i))))
    end:
a:= n-> b(n, 0):
seq(a(n), n=0..23);

b[n_, i_] := b[n, i] = If[n == 0, 1, Max[Table[
     b[n - If[i == 0, j, 1], j] Prime[j], {j, 1, If[i == 0, n, i]}]]];
a[n_] := b[n, 0];
a /@ Range[0, 23] (* Jean-François Alcover, May 03 2021, after Alois P. Heinz *)
(* Second program: extract data from the concise a-file of 10000 terms: *)
With[{nn = 23 (* set nn <= 10000 as desired *)}, Prime[#1]^#2 & @@ # & /@ Map[ToExpression /@ {StringTrim[#1, "p"], #2} & @@ StringSplit[#, "^"] &, Import["https://oeis.org/A332979/a332979.txt", "Data"][[1 ;; nn, -1]] ] ] (* Michael De Vlieger, Aug 22 2022 *)

a(n) = A332977(A011782(n)).

A329637 Square array A(n, k) = A329644(prime(n)^k), read by falling antidiagonals: (1,1), (1,2), (2,1), (1,3), (2,2), (3,1), ...

Original entry on oeis.org

1, 1, 1, 4, -1, 1, 0, 4, -5, 1, 24, -16, 4, -13, 1, -8, 40, -48, 4, -29, 1, 104, -88, 72, -112, 4, -61, 1, -48, 184, -248, 136, -240, 4, -125, 1, 352, -400, 344, -568, 264, -496, 4, -253, 1, 80, 544, -1104, 664, -1208, 520, -1008, 4, -509, 1, 1424, -784, 928, -2512, 1304, -2488, 1032, -2032, 4, -1021, 1

Offset: 1

Antti Karttunen, Nov 22 2019

			The top left corner of the array:
   n   p_n |k=1,     2, 3,      4,     5,      6,     7,       8,      9,      10
  ---------+----------------------------------------------------------------------
   1 ->  2 |  1,     1, 4,      0,    24,     -8,   104,     -48,    352,      80,
   2 ->  3 |  1,    -1, 4,    -16,    40,    -88,   184,    -400,    544,    -784,
   3 ->  5 |  1,    -5, 4,    -48,    72,   -248,   344,   -1104,    928,   -2512,
   4 ->  7 |  1,   -13, 4,   -112,   136,   -568,   664,   -2512,   1696,   -5968,
   5 -> 11 |  1,   -29, 4,   -240,   264,  -1208,  1304,   -5328,   3232,  -12880,
   6 -> 13 |  1,   -61, 4,   -496,   520,  -2488,  2584,  -10960,   6304,  -26704,
   7 -> 17 |  1,  -125, 4,  -1008,  1032,  -5048,  5144,  -22224,  12448,  -54352,
   8 -> 19 |  1,  -253, 4,  -2032,  2056, -10168, 10264,  -44752,  24736, -109648,
   9 -> 23 |  1,  -509, 4,  -4080,  4104, -20408, 20504,  -89808,  49312, -220240,
  10 -> 29 |  1, -1021, 4,  -8176,  8200, -40888, 40984, -179920,  98464, -441424,
  11 -> 31 |  1, -2045, 4, -16368, 16392, -81848, 81944, -360144, 196768, -883792,

Cf. A000079, A000203, A000225, A075708, A182944, A329610, A329644, A329890.
Rows 1-2: A329891, A329892 (from n>=1).
Column 1: A000012, Column 2: -A036563(n) (from n>=1), Column 3: A010709.

up_to = 105;
A329890(n) = if(1==n,1,sigma((2^n)-1)-sigma((2^(n-1))-1));
A329637sq(n,k) = ((2^(n+k-1)) - (((2^n)-1) * A329890(k)));
A329637list(up_to) = { my(v = vector(up_to), i=0); for(a=1,oo, for(col=1,a, i++; if(i > up_to, return(v)); v[i] = A329637sq(col,(a-(col-1))))); (v); };
v329637 = A329637list(up_to);
A329637(n) = v329637[n];

A(n, k) = A329644(A182944(n, k)).

A(n, k) = A000079(n+k-1) - (A000225(n) * A329890(k)).

A320775 a(n) is the least exponent k greater than 1 such that prime(n)^k starts and ends in prime(n).

Original entry on oeis.org

21, 41, 24, 33, 171, 361, 461, 471, 1281, 1091, 231, 221, 236, 61, 861, 2761, 241, 546, 3261, 1991, 6081, 421, 9541, 5731, 4461, 1621, 21501, 10381, 5051, 1301, 16301, 30051, 18601, 13601, 3171, 8991, 7561, 3201, 33501, 8701, 17351, 5601, 13551, 901, 10301, 871

Offset: 1

Paolo P. Lava, Dec 03 2018

a(n) always exists. Let p be a prime other than 2 or 5, and m its length in base 10. Let r be the multiplicative order of p mod 10^m. Then p^k ends in p if and only if k-1 is a multiple of r. p^(j*r+1) starts with p if and only if for some integer s, s + log_10(p)) <= (j*r+1)*log_10(p) < s + frac(log_10(p+1)). This is true for some j because r*log_10(p) is irrational and the fractional parts of the multiples of an irrational number are dense in [0,1]. - Robert Israel, Dec 12 2018
If all integers are considered instead of only primes, not all of them can satisfy the requirement. For instance see A075823 for two digits numbers.
Record values beyond 10^5 are: a(51) = 138801, a(74) = 193701, a(88) = 1766101. Also, a(98) = 282076 and a(100) = 438501 would be record values if not preceded by a(88). - M. F. Hasler, Dec 14 2018

			2^21 = 2097152 and 21 is the least exponent;
3^41 = 36472996377170786403 and 41 is the least exponent.

M. F. Hasler, Table of n, a(n) for n = 1..100
Carlos Rivera, Puzzle 934. The prime 7499, The Prime Puzzles and Problems Connection.
Carlos Rivera, Conjecture 81, The Prime Puzzles and Problems Connection.

Cf. A000040, A075823, A182944.

f:= proc(n) local p, k,m,q,r;
  p:= ithprime(n);
  m:= ilog10(p)+1;
  q:= numtheory:-order(p,10^m);
  for k from q+1 by q do
    r:= p^k;
    if p = floor(r/10^(ilog10(r)+1-m))
      then return k
    fi;
  od
end proc:
f(1):= 21: f(3):= 24:
map(f, [$1..50]); # Robert Israel, Dec 12 2018

a[p_] := Module[{d=IntegerDigits[p]}, nd=Length[d];k=2; While[IntegerDigits[p^k][[1;;nd]] != d || IntegerDigits[p^k][[-nd;;-1]] != d, k++]; k]; a/@Prime@Range@10 (* Amiram Eldar, Dec 10 2018 *)

isokd(d, dpk) = {for (i=1, #d, if (dpk[i] != d[i], return (0));); return (1);}
isok(p, k) = {my(dpk=digits(p^k), d = digits(p)); if (!isokd(d, dpk), return (0)); isokd(Vecrev(d), Vecrev(dpk));}
a(n) = {my(k=2, p = prime(n)); while (!isok(p, k), k++); k;} \\ Michel Marcus, Dec 10 2018

apply( {A320775(n, d=logint(n=prime(n), 10)+1, K=if(n>5||n==3,znorder(Mod(n, 10^d)),n+18), f(x)=x\10^(logint(x, 10)+1-d))=forstep(k=1+K,oo,K, n==f(n^k)&&return(k))}, [1..20]) \\ Define A320775 & test it via apply(). - M. F. Hasler, Dec 10 2018

A356627 Primes whose powers appear in A332979.

Original entry on oeis.org

2, 3, 5, 7, 11, 17, 29, 37, 41, 59, 67, 71, 97, 127, 149, 191, 223, 269, 307, 347, 419, 431, 557, 563, 569, 587, 593, 599, 641, 727, 809, 937, 967, 1009, 1213, 1277, 1423, 1861, 1973, 2237, 2267, 2657, 3163, 3299, 3449, 3457, 3527, 3907, 4001, 4211, 4441, 4637

Offset: 1

Michael De Vlieger, Sep 27 2022

nonn

Maxima of row n > 0 of A005940, A182944, and A182945 are powers of these primes.

Indices k of primes, A000040(k), listed here show an interesting correlation with the function f(k) = A000040(k) - A302334(k). - Peter Munn, Sep 29 2022

			5 | A332979(5..7), thus 5 is in the sequence.
7 | A332979(8), thus 7 is in the sequence.
13 does not divide any term in A332979, so it is not a term in this sequence.

Michael De Vlieger, Table of n, a(n) for n = 1..100
Michael De Vlieger, Plot A332979(n) = p^e at (e, pi(p)) for n = 1..360. The primes p are labeled in bold and appear in this sequence. The least and greatest exponents of p^e are labeled in italic.

Cf. A000040, A000961, A005940, A180944, A180945, A302334, A332979.

Prime@ Union@ Table[MaximalBy[Table[{k, n - k}, {k, n}], Prime[#1]^#2 & @@ # &][[1, 1]], {n, 2^10}]
(* or use concise file in A332979 *)
Prime /@ Union@ Rest@ Map[ToExpression@ StringTrim[#, "p"] & @@ StringSplit[#, "^"] &, Import["https://oeis.org/A332979/a332979.txt", "Data"][[All, -1]]]

cp's OEIS Frontend

A182945 Array of prime powers p^j, as transpose of A182944.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Magma

Maple

Mathematica

A062457 a(n) = prime(n)^n.

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

Magma

Maple

Mathematica

PARI

Formula

A329332 Table of powers of squarefree numbers, powers of A019565(n) in increasing order in row n. Square array A(n,k) n >= 0, k >= 0 read by descending antidiagonals.

Views

Author

Keywords

Comments

Examples

Crossrefs

Formula

A329050 Square array A(n,k) = prime(n+1)^(2^k), read by descending antidiagonals (0,0), (0,1), (1,0), (0,2), (1,1), (2,0), ...; Fermi-Dirac primes (A050376) in matrix form, sorted into rows by their prime divisor.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Mathematica

PARI

Formula

Extensions

A284457 Square array whose rows list numbers with the same squarefree kernel (A007947): Transpose of A284311.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Mathematica

PARI

Scheme

Formula

Extensions

A319075 Square array T(n,k) read by antidiagonal upwards in which row n lists the n-th powers of primes, hence column k lists the powers of the k-th prime, n >= 0, k >= 1.

Views

Author

Keywords

Comments

Examples

Crossrefs

Programs

PARI

Formula

A332979 Largest integer m satisfying Omega(m) + pi(gpf(m)) - [m<>1] = n.

Views

Author

Keywords

Comments

Links

Crossrefs

Programs

Maple