cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A253883 Permutation of natural numbers: a(n) = A243505(A122111(n)).

Original entry on oeis.org

1, 2, 8, 4, 6, 16, 1024, 3, 64, 256, 20, 128, 1073741824, 16384, 18, 32, 240, 512, 3538944, 48, 524288, 288, 8640, 5, 32768, 4398046511104, 27, 2097152, 214990848, 65536, 660, 12, 162, 37778931862957161709568, 134217728, 4096
Offset: 1

Views

Author

Antti Karttunen, Jan 17 2015

Keywords

Comments

Term a(37) has 310 decimal digits and its binary representation is 1028 bits long.

Crossrefs

Inverse: A253884.
Similar permutations: A253791, A253891, A122111, A243505.
Cf. also A253890.

Programs

Formula

a(n) = A243505(A122111(n)).

A280491 a(n) = gcd(n,A122111(n)).

Original entry on oeis.org

1, 2, 1, 1, 1, 6, 1, 1, 9, 2, 1, 2, 1, 2, 3, 1, 1, 3, 1, 20, 3, 2, 1, 2, 1, 2, 1, 4, 1, 30, 1, 1, 3, 2, 1, 3, 1, 2, 3, 4, 1, 6, 1, 4, 5, 2, 1, 2, 1, 5, 3, 4, 1, 1, 1, 56, 3, 2, 1, 6, 1, 2, 1, 1, 1, 6, 1, 4, 3, 10, 1, 3, 1, 2, 75, 4, 1, 6, 1, 4, 1, 2, 1, 84, 1, 2, 3, 8, 1, 10, 1, 4, 3, 2, 1, 2, 1, 1, 1, 1, 1, 6, 1, 8, 15, 2, 1, 1, 1, 10, 3, 8, 1, 6, 1, 4, 1, 2
Offset: 1

Views

Author

Antti Karttunen, Jan 09 2017

Keywords

Crossrefs

Cf. A122111, A280490, also A280489.
Cf. A088902 (the fixed points, n for which a(n) = n).

Programs

Formula

a(n) = gcd(n,A122111(n)).
a(n) = n / A280490(n).
Other identities. For all n >= 1:
a(A122111(n)) = a(n).

A322863 Permutation of natural numbers: a(0) = 1; for n >= 1, a(n) = A005940(1+A122111(n)).

Original entry on oeis.org

1, 2, 3, 5, 4, 7, 9, 11, 6, 10, 25, 13, 15, 17, 49, 21, 8, 19, 16, 23, 35, 55, 121, 29, 27, 36, 169, 50, 77, 31, 81, 37, 12, 91, 289, 225, 30, 41, 361, 187, 125, 43, 625, 47, 143, 147, 529, 53, 45, 154, 90, 247, 221, 59, 28, 1225, 343, 391, 841, 61, 105, 67, 961, 605, 18, 5929, 2401, 71, 323, 551, 525, 73, 22, 79, 1369, 84, 437, 429, 14641, 83
Offset: 0

Views

Author

Antti Karttunen, Dec 30 2018

Keywords

Comments

Note the indexing: the domain starts from 0, but the range excludes zero.

Crossrefs

Inverse permutation: A322864.

Programs

  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t };
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A322863(n) = if(!n,1,A005940(1+A122111(n)));

Formula

a(0) = 1; for n >= 1, a(n) = A005940(1+A122111(n)).
For all n >= 1:
a(prime(n)) = prime(1+n).
A001222(a(n)) = A322867(n).

A331170 a(n) = min(n, A122111(n)), where A122111 conjugates the prime factorization of n.

Original entry on oeis.org

1, 2, 3, 3, 5, 6, 7, 5, 9, 10, 11, 10, 13, 14, 15, 7, 17, 15, 19, 20, 21, 22, 23, 14, 25, 26, 25, 28, 29, 30, 31, 11, 33, 34, 35, 21, 37, 38, 39, 28, 41, 42, 43, 44, 45, 46, 47, 22, 49, 45, 51, 52, 53, 35, 55, 56, 57, 58, 59, 42, 61, 62, 63, 13, 65, 66, 67, 68, 69, 70, 71, 33, 73, 74, 75, 76, 77, 78, 79, 44, 49, 82, 83, 84, 85, 86, 87, 88, 89, 70, 91, 92, 93, 94, 95, 26, 97, 98, 99, 63
Offset: 1

Views

Author

Antti Karttunen, Jan 12 2020

Keywords

Comments

For all i, j:
a(i) = a(j) => A056239(i) = A056239(j),
a(i) = a(j) => A243503(i) = A243503(j).

Crossrefs

Programs

  • PARI
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A331170(n) = min(n, A122111(n));

A336119 Numbers k such that A122111(k) [the conjugated prime factorization of k] is a square or twice a square.

Original entry on oeis.org

1, 2, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 27, 29, 31, 33, 37, 39, 41, 43, 45, 47, 49, 51, 53, 57, 59, 61, 63, 67, 69, 71, 73, 77, 79, 81, 83, 87, 89, 91, 93, 97, 99, 101, 103, 107, 109, 111, 113, 117, 119, 123, 127, 129, 131, 133, 135, 137, 139, 141, 147, 149, 151, 153, 157, 159, 161, 163, 167, 169, 171, 173
Offset: 1

Views

Author

Antti Karttunen, Jul 14 2020

Keywords

Comments

Sequence A122111(A028982(k)), k >= 1, sorted into ascending order.

Crossrefs

Cf. A000040, A066207 (subsequences), A335909 (characteristic function).
Positions of odd terms in A323173, positions of zeros in A336120 and A336121, positions of ones in A336312.

Programs

A336121 a(1) = 0, and for n > 1, a(n) = [A122111(n) == 3 (mod 4)] + a(A253553(n)).

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 2, 0, 2, 0, 1, 0, 1, 0, 2, 1, 1, 0, 1, 0, 2, 0, 3, 0, 1, 1, 1, 0, 1, 0, 2, 0, 2, 0, 1, 0, 1, 0, 3, 0, 1, 0, 1, 0, 3, 1, 2, 0, 1, 0, 1, 0, 1, 0, 3, 1, 2, 0, 1, 0, 1, 0, 2, 0, 1, 1, 1, 0, 2, 0, 3, 0, 1, 0, 1, 1, 1, 0, 2, 0, 3, 0, 1, 0, 1, 1, 3, 0, 2, 0, 2, 0, 2, 0, 2, 1
Offset: 1

Views

Author

Antti Karttunen, Jul 17 2020

Keywords

Comments

Positions for the first occurrence of each n, for n >= 0, are: 1, 4, 16, 32, 144, 512, 2048, 6912, 20736, 62208, ...

Crossrefs

Cf. A336119 (positions of zeros).

Programs

  • PARI
    A253553(n) = if(n<=2,1,my(f=factor(n), k=#f~); if(f[k,2]>1,f[k,2]--,f[k,1] = precprime(f[k,1]-1)); factorback(f));
    A336121(n) = if(1==n,0,(3==A336124(n))+A336121(A253553(n)));

Formula

a(1) = 0, and for n > 1, a(n) = [A336124(n) == 3] + a(A253553(n)).
a(n) = A000120(A336120(n)).
a(n) = A292377(A122111(n)).
a(n) = A001222(n) - A336123(n).

A350066 Symmetric square array A(n,k) = A122111(A122111(n) * A122111(k)), n >= 1, k >= 1, read by antidiagonals.

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 4, 5, 5, 4, 5, 6, 7, 6, 5, 6, 7, 10, 10, 7, 6, 7, 10, 11, 9, 11, 10, 7, 8, 11, 14, 14, 14, 14, 11, 8, 9, 12, 13, 15, 13, 15, 13, 12, 9, 10, 15, 20, 22, 22, 22, 22, 20, 15, 10, 11, 14, 21, 18, 17, 21, 17, 18, 21, 14, 11, 12, 13, 22, 25, 28, 26, 26, 28, 25, 22, 13, 12, 13, 20, 17, 21, 33, 30, 19, 30, 33, 21, 17, 20, 13
Offset: 1

Views

Author

Antti Karttunen, Dec 13 2021

Keywords

Comments

A122111 is a self-inverse permutation, so this array represents a binary operation A(.,.) over the positive integers that is isomorphic to multiplication. Its primes are the positive powers of 2 (as defined by standard multiplication): 2, 4, 8, 16, 32, ... . The positive powers of 2, as defined by A(.,.), are the prime numbers as we usually understand them: 2, 3, 5, 7, 11, ... . - Peter Munn, Aug 04 2022

Examples

			The top left 15 X 15 corner of the array:
   1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11,  12, 13, 14,  15,
   2,  3,  5,  6,  7, 10, 11, 12, 15, 14, 13,  20, 17, 22,  21,
   3,  5,  7, 10, 11, 14, 13, 20, 21, 22, 17,  28, 19, 26,  33,
   4,  6, 10,  9, 14, 15, 22, 18, 25, 21, 26,  30, 34, 33,  35,
   5,  7, 11, 14, 13, 22, 17, 28, 33, 26, 19,  44, 23, 34,  39,
   6, 10, 14, 15, 22, 21, 26, 30, 35, 33, 34,  42, 38, 39,  55,
   7, 11, 13, 22, 17, 26, 19, 44, 39, 34, 23,  52, 29, 38,  51,
   8, 12, 20, 18, 28, 30, 44, 27, 50, 42, 52,  45, 68, 66,  70,
   9, 15, 21, 25, 33, 35, 39, 50, 49, 55, 51,  70, 57, 65,  77,
  10, 14, 22, 21, 26, 33, 34, 42, 55, 39, 38,  66, 46, 51,  65,
  11, 13, 17, 26, 19, 34, 23, 52, 51, 38, 29,  68, 31, 46,  57,
  12, 20, 28, 30, 44, 42, 52, 45, 70, 66, 68,  63, 76, 78, 110,
  13, 17, 19, 34, 23, 38, 29, 68, 57, 46, 31,  76, 37, 58,  69,
  14, 22, 26, 33, 34, 39, 38, 66, 65, 51, 46,  78, 58, 57,  85,
  15, 21, 33, 35, 39, 55, 51, 70, 77, 65, 57, 110, 69, 85,  91,
		

Crossrefs

Cf. A122111, A297002 (main diagonal), A253550 (after its initial term, gives row 2 / column 2 from the second term onward).
See the formula section for the relationships with A003961, A061142.
Cf. also A003991, A129595, A331590.

Programs

  • PARI
    up_to = 105;
    A122111(n) = if(1==n,n,my(f=factor(n), es=Vecrev(f[,2]),is=concat(apply(primepi,Vecrev(f[,1])),[0]),pri=0,m=1); for(i=1, #es, pri += es[i]; m *= prime(pri)^(is[i]-is[1+i])); (m));
    A350066sq(n,k) = A122111(A122111(n)*A122111(k));
    A350066list(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] = A350066sq(col,(a-(col-1))))); (v); };
    v350066 = A350066list(up_to);
    A350066(n) = v350066[n]; \\ Antti Karttunen, Dec 13 2021

Formula

A(n, A061142(n)) = A003961(n). - Peter Munn, Aug 04 2022

A253884 Permutation of natural numbers: a(n) = A122111(A243506(n)).

Original entry on oeis.org

1, 2, 8, 4, 24, 5, 8192, 3, 64, 512, 393216, 32, 7077888, 320, 384, 6, 3802951800684688204490109616128, 15, 300578991243264, 11, 1073741824, 5184, 1134000, 128, 100, 1664, 27, 864, 392318858461667547739736838950479151006397215279002157056000, 65536, 9822276308431282926640601754292746977280, 16, 1215
Offset: 1

Views

Author

Antti Karttunen, Jan 17 2015

Keywords

Crossrefs

Inverse: A253883.
Similar permutations: A253792, A253892, A122111, A243506.

Programs

Formula

a(n) = A122111(A243506(n)).

A323167 a(n) = A294898(A122111(n)).

Original entry on oeis.org

0, 0, 0, 0, 0, -2, 0, 2, 3, -6, 0, 0, 0, -14, -5, 3, 0, 2, 0, -4, -21, -30, 0, 1, 10, -62, 16, -12, 0, -16, 0, 7, -53, -126, -16, 7, 0, -254, -117, -3, 0, -52, 0, -28, 4, -510, 0, 5, 38, 8, -245, -60, 0, 19, -68, -11, -501, -1022, 0, -15, 0, -2046, -20, 9, -172, -124, 0, -124, -1013, -58, 0, 16, 0, -4094, 22, -252, -42, -268, 0, 1, 38
Offset: 1

Views

Author

Antti Karttunen, Jan 10 2019

Keywords

Crossrefs

Programs

Formula

a(n) = A294898(A122111(n)).
a(n) = A323174(n) - A322867(n).

A329607 a(n) = A007947(A122111(n)).

Original entry on oeis.org

1, 2, 2, 3, 2, 6, 2, 5, 3, 6, 2, 10, 2, 6, 6, 7, 2, 15, 2, 10, 6, 6, 2, 14, 3, 6, 5, 10, 2, 30, 2, 11, 6, 6, 6, 21, 2, 6, 6, 14, 2, 30, 2, 10, 10, 6, 2, 22, 3, 15, 6, 10, 2, 35, 6, 14, 6, 6, 2, 42, 2, 6, 10, 13, 6, 30, 2, 10, 6, 30, 2, 33, 2, 6, 15, 10, 6, 30, 2, 22, 7, 6, 2, 42, 6, 6, 6, 14, 2, 70, 6, 10, 6, 6, 6, 26, 2, 15, 10, 21, 2, 30, 2, 14, 30
Offset: 1

Views

Author

Antti Karttunen, Nov 17 2019

Keywords

Crossrefs

Programs

  • Mathematica
    Block[{f}, f[1] = 1; f[n_] := Module[{l = #, m = 0}, Times @@ Power @@@ Table[l -= m; l = DeleteCases[l, 0]; {Prime@ Length@ l, m = Min@ l}, Length@ Union@ l]] &@ Catenate[ConstantArray[PrimePi[#1], #2] & @@@ FactorInteger@ n]; Array[If[# < 1, 0, Sum[EulerPhi[d] Abs@ MoebiusMu[d], {d, Divisors[#]}]] &@ f[#] &, 105]] (* Michael De Vlieger, Nov 18 2019, after JungHwan Min at A122111. *)
  • PARI
    A007947(n) = factorback(factorint(n)[, 1]);
    A064989(n) = {my(f); f = factor(n); if((n>1 && f[1,1]==2), f[1,2] = 0); for (i=1, #f~, f[i,1] = precprime(f[i,1]-1)); factorback(f)};
    A122111(n) = if(1==n,n,prime(bigomega(n))*A122111(A064989(n)));
    A329607(n) = A007947(A122111(n));

Formula

a(n) = A122111(A071364(n)).
A181821(a(n)) = A329600(n).
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