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.

Showing 1-7 of 7 results.

A168364 a(n) = n^5*(n^2 + 1)/2.

Original entry on oeis.org

0, 1, 80, 1215, 8704, 40625, 143856, 420175, 1064960, 2421009, 5050000, 9824111, 18040320, 31559905, 52975664, 85809375, 134742016, 205879265, 307054800, 448173919, 641600000, 902586321, 1249755760, 1705630895, 2297217024
Offset: 0

Views

Author

N. J. A. Sloane, Dec 11 2009

Keywords

Crossrefs

Cf. A000578 (first differences of squares of triangular numbers), A357178 (of their cubes), A059977 (partial sums), A000217.

Programs

  • Magma
    [n^5*(n^2+1)/2: n in [0..30]]; // Vincenzo Librandi, Aug 28 2011
  • Mathematica
    Table[n^5(n^2+1)/2,{n,0,25}]  (* Harvey P. Dale, Apr 22 2011 *)
    LinearRecurrence[{8, -28, 56, -70, 56, -28, 8, -1},{0, 1, 80, 1215, 8704, 40625, 143856, 420175}, 50] (* G. C. Greubel, Jul 19 2016 *)

Formula

G.f.: x*(1 + 72*x + 603*x^2 + 1168*x^3 + 603*x^4 + 72*x^5 + x^6)/(1-x)^8. - Harvey P. Dale, Apr 22 2011
a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8). - G. C. Greubel, Jul 19 2016
a(n) = A000217(n)^4 - A000217(n-1)^4. - Kelvin Voskuijl, Jan 16 2025

A059978 a(n) = binomial(n+2,n)^6.

Original entry on oeis.org

1, 729, 46656, 1000000, 11390625, 85766121, 481890304, 2176782336, 8303765625, 27680640625, 82653950016, 225199600704, 567869252041, 1340095640625, 2985984000000, 6327518887936, 12827693806929, 25002110044521, 47045881000000, 85766121000000, 151939915084881
Offset: 0

Views

Author

Robert G. Wilson v, Mar 06 2001

Keywords

Comments

Number of 6-dimensional cage assemblies.

References

  • Clifford A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Oxford University Press, 2001, p. 325.

Crossrefs

Programs

  • Maple
    with (combinat):seq(mul(stirling2(n+1,n),k=1..6),n=1..18); # Zerinvary Lajos, Dec 14 2007
  • Mathematica
    m = 6; Table[n^m (n + 1)^m/2^m, {n, 1, 24}]

Formula

G.f.: (x^10 + 716*x^9 + 37257*x^8 + 450048*x^7 + 1822014*x^6 +2864328*x^5 + 1822014*x^4 + 450048*x^3 + 37257*x^2 + 716*x + 1)/(1-x)^13. - Colin Barker, Jul 09 2012
G.f.: 6F5([3,3,3,3,3,3], [1,1,1,1,1], z). - Benedict W. J. Irwin, Mar 14 2016
a(n) = (1/16)*( 3*S(7,n+1) + 10*S(9,n+1) + 3*S(11,n+1) ), where S(r,n) = Sum_{k = 1..n} k^r. Cf. A059977 and A059980. - Peter Bala, Jul 02 2019
From Amiram Eldar, May 15 2022: (Start)
Sum_{n>=0} 1/a(n) = 2688*Pi^2 + 448*Pi^4/15 + 128*Pi^6/945 - 29568.
Sum_{n>=0} (-1)^n/a(n) = 29568 - 32256*log(2) - 5376*zeta(3) - 720*zeta(5). (End)

Extensions

Better definition from Zerinvary Lajos, May 23 2006

A248619 a(n) = (n*(n+1))^4.

Original entry on oeis.org

0, 16, 1296, 20736, 160000, 810000, 3111696, 9834496, 26873856, 65610000, 146410000, 303595776, 592240896, 1097199376, 1944810000, 3317760000, 5473632256, 8767700496, 13680577296, 20851360000, 31116960000, 45558341136, 65554433296, 92844527616, 129600000000
Offset: 0

Views

Author

Eugene Chong, Oct 09 2014

Keywords

Crossrefs

Cf. A016744, A059977; A002378: n*(n+1); A035287: n^2 *(n-1)^2; A060459: n^3*(n+1)^3.
Cf. A327773.

Programs

  • Magma
    [(n*(n+1))^4: n in [0..30]]; // Vincenzo Librandi, Oct 16 2014
  • Maple
    [ seq(n^4*(n+1)^4, n = 0..100) ];
  • Mathematica
    Table[(n (n + 1))^4, {n, 0, 70}] (* or *) CoefficientList[Series[16 x (1 + 72 x + 603 x^2 + 1168 x^3 + 603 x^4 + 72 x^5 + x^6)/(1 - x)^9, {x, 0, 30}], x] (* Vincenzo Librandi, Oct 16 2014 *)
    LinearRecurrence[{9,-36,84,-126,126,-84,36,-9,1},{0,16,1296,20736,160000,810000,3111696,9834496,26873856},30] (* Harvey P. Dale, Sep 09 2016 *)

Formula

a(n) = A002378(n)^4 = A016744(A000217(n)).
a(n) = 16*A059977(n) for n>0.
G.f.: 16*x*(1 + 72*x + 603*x^2 + 1168*x^3 + 603*x^4 + 72*x^5 + x^6)/(1 - x)^9. - Vincenzo Librandi, Oct 16 2014
Sum_{n>=1} 1/a(n) = A327773 = -35 + 10*Pi^2/3 + Pi^4/45. - Vaclav Kotesovec, Sep 25 2019

Extensions

Terms a(76) and beyond corrected by Andrew Howroyd, Feb 20 2018

A059980 Number of 8-dimensional cage assemblies.

Original entry on oeis.org

1, 6561, 1679616, 100000000, 2562890625, 37822859361, 377801998336, 2821109907456, 16815125390625, 83733937890625, 360040606269696, 1370114370683136, 4702525276151521, 14774554437890625, 42998169600000000, 117033789351264256, 300283484326400961
Offset: 1

Views

Author

Robert G. Wilson v, Mar 06 2001

Keywords

References

  • Clifford A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Oxford University Press, 2001, p. 325.

Crossrefs

Programs

  • Mathematica
    m = 8; Table[n^m (n + 1)^m/2^m, {n, 1, 18}]

Formula

G.f.: -x*(x^14 +6544*x^13 +1568215*x^12 +72338144*x^11 +1086859301*x^10 +6727188848*x^9 +19323413187*x^8 +27306899520*x^7 +19323413187*x^6 +6727188848*x^5 +1086859301*x^4 +72338144*x^3 +1568215*x^2 +6544*x +1)/(x-1)^17. - Colin Barker, Jul 09 2012
From Peter Bala, Jul 02 2019 (Start)
a(n) = (n*(n + 1)/2)^8.
a(n) = (1/16)*( S(9,n) + 7*S(11,n) + 7*S(13,n) + S(15,n) ), where S(r,n) = Sum_{k = 1..n} k^r. Cf. A059977 and A059978. (End)
From Amiram Eldar, May 15 2022: (Start)
Sum_{n>=1} 1/a(n) = 146432*Pi^2 + 5632*Pi^4/3 + 2048*Pi^6/105 + 256*Pi^8/4725 - 1647360.
Sum_{n>=1} (-1)^(n+1)/a(n) = 1647360 - 1757184*log(2) - 304128*zeta(3) - 57600*zeta(5) - 4032*zeta(7). (End)

A271535 a(n) = ( n*(n + 1)*(2*n + 1)/6 )^2.

Original entry on oeis.org

0, 1, 25, 196, 900, 3025, 8281, 19600, 41616, 81225, 148225, 256036, 422500, 670761, 1030225, 1537600, 2238016, 3186225, 4447881, 6100900, 8236900, 10962721, 14402025, 18696976, 24010000, 30525625, 38452401, 48024900, 59505796, 73188025, 89397025, 108493056
Offset: 0

Views

Author

Vincenzo Librandi, Apr 20 2016

Keywords

Crossrefs

Programs

  • Magma
    [(n*(n+1)*(2*n+1)/6)^2: n in [0..50]];
    
  • Mathematica
    Table[(n (n + 1) (2 n + 1)/6)^2, {n, 0, 50}]
  • PARI
    vector(100, n, n--; (n*(n + 1)*(2*n + 1)/6)^2) \\ Altug Alkan, Apr 21 2016

Formula

G.f.: x*(1 + 18*x + 42*x^2 + 18*x^3 + x^4)/(1 - x)^7.
a(n) = Sum_{j=1..n} Sum_{i=1..n} (i*j)^2. - Alexander Adamchuk, Oct 26 2004
E.g.f.: x*(36 + 414*x + 744*x^2 + 393*x^3 + 72*x^4 + 4*x^5)*exp(x)/36. - Ilya Gutkovskiy, Apr 21 2016
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).
Sum_{i = 0..n} a(i) = n*(n + 1)*(n + 2)*(2*n + 1)*(2*n + 3)*(5*n^2 + 10*n - 1)/1260. [See Carmichael - DeLand in Links section, page 132.]
a(n) = A000330(n)^2. - Ray Chandler, Apr 21 2016
Sum_{n>=1} 1/a(n) = 84*Pi^2 - 828. - Amiram Eldar, Feb 25 2023

Extensions

Edited by Bruno Berselli, Apr 22 2016

A202107 a(n) = n^4*(n+1)^4/8.

Original entry on oeis.org

2, 162, 2592, 20000, 101250, 388962, 1229312, 3359232, 8201250, 18301250, 37949472, 74030112, 137149922, 243101250, 414720000, 684204032, 1095962562, 1710072162, 2606420000, 3889620000, 5694792642, 8194304162, 11605565952, 16200000000, 22313281250, 30356972802
Offset: 1

Views

Author

Martin Renner, Dec 11 2011

Keywords

Comments

A relation between fourth powers and the sum of fifth and seventh powers. See the first formula, which is from Beiler.

References

  • Albert H. Beiler, Recreations in the theory of numbers, New York, Dover, (2nd ed.) 1966, p. 161.

Crossrefs

Programs

Formula

a(n) = 2*(Sum_{k=1..n} k)^4 = Sum_{k=1..n} (k^5 + k^7).
a(n) = 2*A059977(n-1).
a(n) = A000539(n) + A000541(n).
G.f.: -2*x*(1+72*x+603*x^2+1168*x^3+603*x^4+72*x^5+x^6) / (x-1)^9. - R. J. Mathar, Dec 13 2011
a(n) = 2*(A000217(n)^4). - Zak Seidov, Jan 21 2012
From Amiram Eldar, Apr 09 2024: (Start)
Sum_{n>=1} 1/a(n) = 8*Pi^4/45 + 80*Pi^2/3 - 280.
Sum_{n>=1} (-1)^(n+1)/a(n) = 280 - 320*log(2) - 48*zeta(3). (End)

A091480 Table of multigraphs (by antidiagonals) with n (>=1) nodes and k (>=0) edges. Each type of object labeled from its own label set.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 1, 3, 1, 0, 1, 9, 6, 1, 0, 1, 27, 36, 10, 1, 0, 1, 81, 216, 100, 15, 1, 0, 1, 243, 1296, 1000, 225, 21, 1, 0, 1, 729, 7776, 10000, 3375, 441, 28, 1, 0, 1, 2187, 46656, 100000, 50625, 9261, 784, 36, 1, 0, 1, 6561, 279936, 1000000, 759375
Offset: 1

Views

Author

Christian G. Bower, Jan 13 2004

Keywords

Examples

			1  0   0    0     0 ...
1  1   1    1     1 ...
1  3   9   27    81 ...
1  6  36  216  1296 ...
1 10 100 1000 10000 ...
		

References

  • F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 114 (2.4.44).

Crossrefs

Columns 0-8: A000012, A000217(n-1), A000537(n-1), A059827(n-1), A059977(n-1), A059860(n-1), A059978(n-1), A059979(n-1), A059980(n-1).
Cf. A091478.

Formula

a(n, k) = binomial(n, 2)^k.
Showing 1-7 of 7 results.