A100104 -id:A100104 - cp's OEIS frontend

A000584 Fifth powers: a(n) = n^5.

0, 1, 32, 243, 1024, 3125, 7776, 16807, 32768, 59049, 100000, 161051, 248832, 371293, 537824, 759375, 1048576, 1419857, 1889568, 2476099, 3200000, 4084101, 5153632, 6436343, 7962624, 9765625, 11881376, 14348907, 17210368, 20511149

Offset: 0

N. J. A. Sloane

Totally multiplicative sequence with a(p) = p^5 for prime p. - Jaroslav Krizek, Nov 01 2009
The binomial transform yields A059338. The inverse binomial transform yields the (finite) 0, 1, 30, 150, 240, 120, the 5th row in A019538 and A131689. - R. J. Mathar, Jan 16 2013
Equals sum of odd numbers from n^2*(n-1)+1 (A100104) to n^2*(n+1)-1 (A003777). - Bruno Berselli, Mar 14 2014
a(n) mod 10 = n mod 10. - Reinhard Zumkeller, May 10 2014
Numbers of the form a(n) + a(n+1) + ... + a(n+k) are nonprime for all n, k>=0; this can be proved by the method indicated in the comment in A256581. - Vladimir Shevelev and Peter J. C. Moses, Apr 04 2015

R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. Addison-Wesley, Reading, MA, 1990, p. 255; 2nd. ed., p. 269. Worpitzky's identity (6.37).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Franklin T. Adams-Watters, Table of n, a(n) for n = 0..500
Brady Haran and Simon Pampena, Fifth Root Trick, Numberphile video (2014)
Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992; arXiv:0911.4975 [math.NT], 2009.
Simon Plouffe, 1031 Generating Functions, Appendix to Thesis, Montreal, 1992
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).

Partial sums give A000539.
Cf. A000012, A001477, A000290, A000578, A000583, A062392, A022521 (first differences), A008292, A173018, A123125.
Cf. A013663, A162624, A267316.

a000584 = (^ 5)  -- Reinhard Zumkeller, Nov 11 2012

Range[0,50]^5 (* Vladimir Joseph Stephan Orlovsky, Feb 20 2011 *)

makelist(n^5, n, 0, 30); /* Martin Ettl, Nov 12 2012 */

a(n)=n^5 \\ Charles R Greathouse IV, Jul 28 2015

[n**5 for n in range(30)]  # Zerinvary Lajos, Jun 03 2009

G.f.: x*(1+26*x+66*x^2+26*x^3+x^4) / (x-1)^6. [Simon Plouffe in his 1992 dissertation]
Multiplicative with a(p^e) = p^(5e). - David W. Wilson, Aug 01 2001
E.g.f.: exp(x)*(x+15*x^2+25*x^3+10*x^4+x^5). - Geoffrey Critzer, Jun 12 2013
a(n) = 5*a(n-1) - 10* a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) + 120. - Ant King, Sep 23 2013
a(n) = n + Sum_{j=0..n-1}{k=1..4}binomial(5,k)*j^(5-k). - Patrick J. McNab, Mar 28 2016
From Kolosov Petro, Oct 22 2018: (Start)
a(n) = Sum_{k=1..n} A300656(n,k).
a(n) = Sum_{k=0..n-1} A300656(n,k). (End)
a(n) = Sum_{k=1..5} Eulerian(5, k)*binomial(n+5-k, 5), with Eulerian(5, k) = A008292(5, k), the numbers 1, 26, 66, 26, 1, for n >= 0. Worpitzki's identity for powers of 5. See. e.g., Graham et al., eq. (6, 37) (using A173018, the row reversed version of A123125). - Wolfdieter Lang, Jul 17 2019
From Amiram Eldar, Oct 08 2020: (Start)
Sum_{n>=1} 1/a(n) = zeta(5) (A013663).
Sum_{n>=1} (-1)^(n+1)/a(n) = 15*zeta(5)/16 (A267316). (End)

More terms from Henry Bottomley, Jun 21 2001

A049451 Twice second pentagonal numbers.

Original entry on oeis.org

0, 4, 14, 30, 52, 80, 114, 154, 200, 252, 310, 374, 444, 520, 602, 690, 784, 884, 990, 1102, 1220, 1344, 1474, 1610, 1752, 1900, 2054, 2214, 2380, 2552, 2730, 2914, 3104, 3300, 3502, 3710, 3924, 4144, 4370, 4602, 4840, 5084, 5334, 5590, 5852, 6120, 6394, 6674, 6960, 7252, 7550, 7854

Offset: 0

Joe Keane (jgk(AT)jgk.org)

From Floor van Lamoen, Jul 21 2001: (Start)
Write 1,2,3,4,... in a hexagonal spiral around 0, then a(n) is the sequence found by reading the line from 0 in the direction 0,4,... . The spiral begins:
                            .
                          52
                          . \
            33--32--31--30  51
            /           . \   \
          34  16--15--14  29  50
          /   /       . \   \   \
        35  17   5---4  13  28  49
        /   /   /   . \   \   \   \
      36  18   6   0   3  12  27  48
      /   /   /   /   /   /   /   /
    37  19   7   1---2  11  26  47
      \   \   \         /   /   /
      38  20   8---9--10  25  46
        \   \             /   /
        39  21--22--23--24  45
          \                 /
          40--41--42--43--44
(End)
Number of edges in the join of the complete bipartite graph of order 2n and the cycle graph of order n, K_n,n * C_n. - Roberto E. Martinez II, Jan 07 2002
The average of the first n elements starting from a(1) is equal to (n+1)^2. - Mario Catalani (mario.catalani(AT)unito.it), Apr 10 2003
If Y is a 4-subset of an n-set X then, for n >= 4, a(n-4) is the number of (n-4)-subsets of X having either one element or two elements in common with Y. - Milan Janjic, Dec 28 2007
With offset 1: the maximum possible sum of numbers in an N x N standard Minesweeper grid. - Dmitry Kamenetsky, Dec 14 2008
a(n) = A001399(6*n-2), number of partitions of 6*n-2 into parts < 4. For example a(2)=14 where the partitions of 6*2-2=10 into parts < 4 are [1,1,1,1,1,1,1,1,1,1], [1,1,1,1,1,1,1,1,2], [1,1,1,1,1,1,1,3], [1,1,1,1,1,1,2,2], [1,1,1,1,1,2,3], [1,1,1,1,2,2,2], [1,1,1,1,3,3], [1,1,1,2,2,3], [1,1,2,2,2,2], [1,1,2,3,3], [1,2,2,2,3], [2,2,2,2,2], [1,3,3,3], [2,2,3,3]. - Adi Dani, Jun 07 2011
A003056 is the following array A read by antidiagonals:
  0,  1,  2,  3,  4,  5, ...
  1,  2,  3,  4,  5,  6, ...
  2,  3,  4,  5,  6,  7, ...
  3,  4,  5,  6,  7,  8, ...
  4,  5,  6,  7,  8,  9, ...
  5,  6,  7,  8,  9, 10, ...
and a(n) is the hook sum Sum_{k=0..n} A(n,k) + Sum_{r=0..n-1} A(r,n). - R. J. Mathar, Jun 30 2013
a(n)*Pi is the total length of 3 points circle center spiral after n rotations. The spiral length at each rotation (L(n)) is A016957. The spiral length ratio rounded down [floor(L(n)/L(1))] is A001651. See illustration in links. - Kival Ngaokrajang, Dec 27 2013
Partial sums give A114364. - Leo Tavares, Feb 25 2022
For n >= 1, the continued fraction expansion of sqrt(27*a(n)) is [9n+1; {2, 2n-1, 1, 4, 1, 2n-1, 2, 18n+2}]. - Magus K. Chu, Oct 13 2022

			From _Dmitry Kamenetsky_, Dec 14 2008, with slight rewording by Raymond Martineau (mart0258(AT)yahoo.com), Dec 16 2008: (Start)
For an N x N Minesweeper grid the highest sum of numbers is (N-1)(3*N-2). This is achieved by filling every second row with mines (shown as 'X'). For example, when N=5 the best grids are:
.
  X X X X X
  4 6 6 6 4
  X X X X X
  4 6 6 6 4
  X X X X X
.
  and
.
  2 3 3 3 2
  X X X X X
  4 6 6 6 4
  X X X X X
  2 3 3 3 2
.
each giving a total of 52. (End)

L. B. W. Jolley, Summation of Series, Dover Publications, 1961, p. 12.

Ivan Panchenko, Table of n, a(n) for n = 0..1000
Raghavendra N. Bhat, Cristian Cobeli, and Alexandru Zaharescu, A lozenge triangulation of the plane with integers, arXiv:2403.10500 [math.NT], 2024.
Kival Ngaokrajang, Illustration of 3 points circle center spiral.
Leo Tavares, Illustration: Double Hexagonal Trapezoids.
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Cf. A000567, A001105, A002378, A005449, A033580, A049450.
Similar sequences are listed in A316466.
Cf. A003215, A005408, A114364.

List([0..55], n-> n*(3*n+1)); # G. C. Greubel, Sep 01 2019

a049451 n = n * (3 * n + 1)  -- Reinhard Zumkeller, Jul 07 2012

[n*(3*n+1): n in [0..55]]; // G. C. Greubel, Sep 01 2019

Table[n(3n+1), {n,0,55}] (* or *) CoefficientList[Series[2x(2+x)/(1-x)^3, {x,0,55}], x] (* Michael De Vlieger, Apr 05 2017 *)

a(n)=n*(3*n+1) \\ Charles R Greathouse IV, Sep 24 2015

[n*(3*n+1) for n in range(60)] # Gennady Eremin, Feb 27 2022

[n*(3*n+1) for n in (0..55)] # G. C. Greubel, Sep 01 2019

a(n) = n*(3*n+1).
G.f.: 2*x*(2+x)/(1-x)^3.
Sum_{i=1..n} a(i) = A045991(n+1). - Gary W. Adamson, Dec 20 2006
a(n) = 2*A005449(n). - Omar E. Pol, Dec 18 2008
a(n) = a(n-1) + 6*n -2, n > 0. - Vincenzo Librandi, Aug 06 2010
a(n) = A100104(n+1) - A100104(n). - Reinhard Zumkeller, Jul 07 2012
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) with a(0) = 0, a(1) = 4, a(2) = 14. - Philippe Deléham, Mar 26 2013
a(n) = A174709(6*n+3). - Philippe Deléham, Mar 26 2013
a(n) = (24/(n+2)!)*Sum_{j=0..n} (-1)^(n-j)*binomial(n,j)*j^(n+2). - Bruno Berselli, Jun 04 2013 - after the similar formula of Vladimir Kruchinin in A002411
a(n) = A002061(n+1) + A056220(n). - Bruce J. Nicholson, Sep 21 2017
a(n) = Sum_{i = 2..5} P(i,n), where P(i,m) = m*((i-2)*m-(i-4))/2. - Bruno Berselli, Jul 04 2018
E.g.f.: x*(4 + 3*x)*exp(x). - G. C. Greubel, Sep 01 2019
a(n) = A003215(n) - A005408(n). - Leo Tavares, Feb 25 2022
From Amiram Eldar, Feb 27 2022: (Start)
Sum_{n>=1} 1/a(n) = 3 - Pi/(2*sqrt(3)) - 3*log(3)/2.
Sum_{n>=1} (-1)^(n+1)/a(n) = Pi/sqrt(3) + 2*log(2) - 3. (End)
a(n) = A001105(n) + A002378(n). - Torlach Rush, Jul 11 2022

A162613 Triangle read by rows in which row n lists n terms, starting with n, with gaps = n^2-1 between successive terms.

Original entry on oeis.org

1, 2, 5, 3, 11, 19, 4, 19, 34, 49, 5, 29, 53, 77, 101, 6, 41, 76, 111, 146, 181, 7, 55, 103, 151, 199, 247, 295, 8, 71, 134, 197, 260, 323, 386, 449, 9, 89, 169, 249, 329, 409, 489, 569, 649, 10, 109, 208, 307, 406, 505, 604, 703, 802, 901, 11, 131, 251, 371, 491, 611

Offset: 1

Omar E. Pol, Jul 09 2009

Note that the last term of the n-th row is A100104(n).

			Triangle begins:
  1;
  2,   5;
  3,  11,  19;
  4,  19,  34,  49;
  5,  29,  53,  77, 101;
  6,  41,  76, 111, 146, 181;

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A000578, A100104, A159797, A159798, A162610, A162611, A162612.

Cf. A100855 (row sums). - R. J. Mathar, Jul 20 2009

Table[NestList[#+n^2-1&,n,n-1],{n,11}]//Flatten (* Harvey P. Dale, Feb 24 2016 *)

More terms from Vincenzo Librandi, Aug 02 2010

A255741 Square array read by antidiagonals upwards: T(n,k), n>=1, k>=1, in which row n lists the partial sums of the n-th row of the square array of A255740.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 5, 3, 1, 1, 5, 7, 7, 4, 1, 1, 6, 9, 13, 9, 4, 1, 1, 7, 11, 21, 16, 11, 4, 1, 1, 8, 13, 31, 25, 22, 13, 4, 1, 1, 9, 15, 43, 36, 37, 28, 15, 5, 1, 1, 10, 17, 57, 49, 56, 49, 40, 17, 5, 1, 1, 11, 19, 73, 64, 79, 76, 85, 43, 19, 5, 1, 1, 12, 21, 91, 81, 106, 109, 156, 89, 49, 21, 5, 1

Offset: 1

Omar E. Pol, Mar 05 2015

			The corner of the square array with the first 15 terms of the first 12 rows looks like this:
-------------------------------------------------------------------------
A000012: 1, 1, 1,  1,  1,  1,  1,   1,   1,   1,   1,   1,   1,   1,   1
A070941: 1, 2, 3,  3,  4,  4,  4,   4,   5,   5,   5,   5,   5,   5,   5
A005408: 1, 3, 5,  7,  9, 11, 13,  15,  17,  19,  21,  23,  25,  27,  29
A151788: 1, 4, 7, 13, 16, 22, 28,  40,  43,  49,  55,  67,  73,  85,  97
A147562: 1, 5, 9, 21, 25, 37, 49,  85,  89, 101, 113, 149, 161, 197, 233
A151790: 1, 6,11, 31, 36, 56, 76, 156, 161, 181, 201, 281, 301, 381, 461
A151781: 1, 7,13, 43, 49, 79,109, 259, 265, 295, 325, 475, 505, 655, 805
A151792: 1, 8,15, 57, 64,106,148, 400, 407, 449, 491, 743, 785,1037,1289
A151793: 1, 9,17, 73, 81,137,193, 585, 593, 649, 705,1097,1153,1545,1937
A255764: 1,10,19, 91,100,172,244, 820, 829, 901, 973,1549,1621,2197,2773
A255765: 1,11,21,111,121,211,301,1111,1121,1211,1301,2111,2201,3011,3821
A255766: 1,12,23,133,144,254,364,1464,1475,1585,1695,2795,2905,4005,5105
...

Index entries for sequences related to cellular automata

Rows 1-12: A000012, A070941, A005408, A151788, A147562, A151790, A151781, A151792, A151793, A255764, A255765, A255766.
Columns 1-10: A000012, A000027, A005408, A002061, A000290, A084849, A056107, A053698, A100705, A100104.
Cf. A000120, A255740.

A214084 Triangle read by rows: n-th row = {m: n^2 <= m <= n^3}.

Original entry on oeis.org

0, 1, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56

Offset: 0

Reinhard Zumkeller, Jul 07 2012

Reinhard Zumkeller, Rows n = 0..15 of triangle, flattened

Cf. A100104 (row lengths), A214085 (row sums), A000290 (left edge), A000578 (right edge), A079648 (number of primes per row).

a214084 n k = a214084_tabf !! n !! k
a214084_row n = a214084_tabf !! n
a214084_tabf = zipWith enumFromTo a000290_list a000578_list

A214085 n^2 * (n^4 - n^2 + n + 1) / 2.

Original entry on oeis.org

0, 1, 30, 342, 1960, 7575, 22806, 57820, 129312, 262845, 495550, 879186, 1483560, 2400307, 3747030, 5671800, 8358016, 12029625, 16956702, 23461390, 31924200, 42790671, 56578390, 73884372, 95392800, 121883125, 154238526, 193454730, 240649192, 297070635

Offset: 0

Reinhard Zumkeller, Jul 07 2012

Row sums of the triangle in A214084.

Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).

a214085 n = n^2 * (n^4 - n^2 + n + 1) `div` 2

[n^2*(n^4-n^2+n+1)/2: n in [0..29]]; // Bruno Berselli, Jul 09 2012

Table[n^2 (n^4 - n^2 + n + 1)/2, {n, 0, 29}] (* Bruno Berselli, Jul 09 2012 *)
LinearRecurrence[{7,-21,35,-35,21,-7,1},{0,1,30,342,1960,7575,22806},40] (* Harvey P. Dale, Dec 12 2012 *)

a(n) = n * A000217(n) * A100104(n).
a(n) = A000217(A000578(n)) - A000217(A000290(n) - 1).
G.f.: x*(1+23*x+153*x^2+161*x^3+22*x^4)/(1-x)^7. - Bruno Berselli, Jul 09 2012
a(0)=0, a(1)=1, a(2)=30, a(3)=342, a(4)=1960, a(5)=7575, a(6)=22806, a(n)=7*a(n-1)-21*a(n-2)+35*a(n-3)-35*a(n-4)+21*a(n-5)-7*a(n-6)+a(n-7). - Harvey P. Dale, Dec 12 2012

A380790 Length of the n-th Golomb ruler constructed by the Paul Erdős and Pál Turán formula.

Original entry on oeis.org

20, 110, 308, 1254, 2106, 4760, 6650, 11822, 23954, 29202, 49950, 68060, 78518, 102460, 147446, 203432, 225090, 298418, 354858, 386316, 489484, 568052, 700964, 907920, 1025150, 1086856, 1218944, 1289034, 1436456, 2039620, 2238790, 2561900, 2675472, 3296774, 3430418

Offset: 2

Darío Clavijo, Feb 03 2025

nonn

In October of 1941 Paul Erdős and Pál Turán found that a Golomb ruler could be constructed for every odd prime p.
Such a ruler has the property that the mark or notches are defined by: notch(k) = 2pk + (k^2 mod p) for k in {0..p-1}, with p=A000040(n).
Empirical observation: a(n) satisfies p^3-p^2 <= a(n)/p^3 <= 0.9999.
Except for n=2, a(n) is divisible by p.
Also partial sums of A217793.

			 n | p  | Golomb ruler notches                             | a(n)
---+----+--------------------------------------------------+-------
 2 | 3  | 0, 7,  13                                        | 20
 3 | 5  | 0, 11, 24, 34, 41                                | 110
 4 | 7  | 0, 15, 32, 44, 58, 74,  85                       | 308
 5 | 11 | 0, 23, 48, 75, 93, 113, 135, 159, 185, 202, 221  | 1254

P. Erdös and P. Turán, On a Problem of Sidon in Additive Number Theory, and on some Related Problems, Journal of the London Mathematical Society, Volume s1-16, Issue 4, October 1941, Pages 212-215.
Wikipedia, Golomb ruler
Index entries for sequences related to Golomb rulers

Cf. A000010, A000040, A000330, A048153, A076409, A100104, A127921, A135177, A160378, A217793.

a(n)= if(n==2, return(20));  my(p=prime(n)); if(bitand(p, 3)==1, return((p*(p-1)*(2*p+1))/2)); if(bitand(p, 3)==3, return((p*(p-1)*(2*p+1))/2 - p * qfbclassno(-p)));

from sympy import prime
from math import isqrt
def a(n):
  p = prime(n)
  if p & 3 == 1: return (p*(p-1)*(2*p+1))//2
  m = isqrt(p-1)
  return (p-1) * p**2 + (m*(m+1)*(2*m+1))//6 + sum(pow(k,2,p) for k in range(m+1,p))
print([a(n) for n in range(2, 37) ])

a(n) = Sum_{k=0..p-1} (2*k*p + k^2 mod p), where p is the n-th prime.
a(n) = (p-1)*p^2 + 1 + Sum_{k=2..p-1} (k^2 mod p), where p is the n-th prime.
a(n) = (p-1)*p^2 + A000330(m) + Sum_{k=m+1..p-1} (k^2 mod p), where m = floor(sqrt(p-1)) and p is the n-th prime.
a(n) = (p-1)*p^2 + p*(p-1)*(p+1)/12 - 2*p*(Sum_{k=1..(p-1)/2} floor(k^2/p)), where p is the n-th prime.
a(n) = A100104(A000040(n)) + A048153(A000040(n)) - 1.
a(n) = A100104(A000040(n)) + A076409(n).
a(n) = A160378(A000040(n)), iif A000040(n) = 1 (mod 4).
a(n) = A160378(A000040(n)) - A000040(n)*A355879(n), iif A000040(n) = 3 (mod 4).
a(n) < A000040(n)^3.
a(n) > A000040(n)^3 - A000040(n)^2.
a(n) = 0 mod A000040(n) for n >= 3.
a(n) = Sum_{k=0..A000040(n)-1} A217793(n - 1, k).
a(n) = A135177(n) + A127921(n) - 2*p*(Sum_{k=1..(p-1)/2} floor(k^2/p)), where p = A000040(n).

cp's OEIS Frontend

A000584 Fifth powers: a(n) = n^5.

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A049451 Twice second pentagonal numbers.

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A162613 Triangle read by rows in which row n lists n terms, starting with n, with gaps = n^2-1 between successive terms.

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A255741 Square array read by antidiagonals upwards: T(n,k), n>=1, k>=1, in which row n lists the partial sums of the n-th row of the square array of A255740.

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A214084 Triangle read by rows: n-th row = {m: n^2 <= m <= n^3}.

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A214085 n^2 * (n^4 - n^2 + n + 1) / 2.

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A380790 Length of the n-th Golomb ruler constructed by the Paul Erdős and Pál Turán formula.

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