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 1-4 of 4 results.

A078472 Partial sums of A035282.

Original entry on oeis.org

1, 6, 12, 22, 46, 67, 107, 137, 168, 228, 292, 342, 426, 546, 606, 656, 800, 920, 1044, 1129, 1273, 1473, 1633, 1759, 1850, 2030, 2270, 2510, 2665, 2869, 3089, 3389, 3799, 4119, 4275, 4539, 4819, 5029, 5389, 5689, 5993, 6377, 6797, 6967, 7367, 7871, 8231
Offset: 1

Views

Author

Benoit Cloitre, Dec 31 2002

Keywords

Crossrefs

Distinct terms of A353997.

Programs

  • Mathematica
    f[p_, e_] := Which[p == 5, (5^(e + 1) - 1)/4, (m = Mod[p, 5]) == 2 || m == 3, If[EvenQ[e], (p^(e + 2) - 1)/(p^2 - 1), 0], m == 1 || m == 4, Sum[(k + 1)*(e - k + 1)*p^k, {k, 0, e}]]; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Accumulate[Select[Array[s, 200], # > 0 &]] (* Amiram Eldar, May 13 2022 *)

Extensions

a(20) and a(36) corrected by Georg Fischer, Aug 31 2020

A078473 Expansion of zeta function of icosian ring.

Original entry on oeis.org

1, 0, 0, 5, 6, 0, 0, 0, 10, 0, 24, 0, 0, 0, 0, 21, 0, 0, 40, 30, 0, 0, 0, 0, 31, 0, 0, 0, 60, 0, 64, 0, 0, 0, 0, 50, 0, 0, 0, 0, 84, 0, 0, 120, 60, 0, 0, 0, 50, 0, 0, 0, 0, 0, 144, 0, 0, 0, 120, 0, 124, 0, 0, 85, 0, 0, 0, 0, 0, 0, 144, 0, 0, 0, 0, 200, 0, 0, 160, 126, 91, 0, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Benoit Cloitre, Dec 31 2002

Keywords

Comments

Let zetaI(s) be the zeta function of icosian ring: zetaI(s) = zetaQ(tau)(2s)*zetaQ(tau)(2s-1) where zetaQ(tau)(s) is defined in A035187. Then zetaI(s) = Sum_{n>=1} a(n)/n^(2s).

Crossrefs

Cf. A035187, A035282 (nonzero terms of the sequence), A031363 (n for which a(n) is not zero), A078471.

Programs

  • Mathematica
    f[p_, e_] := Which[p == 5, (5^(e + 1) - 1)/4, (m = Mod[p, 5]) == 2 || m == 3, If[EvenQ[e], (p^(e + 2) - 1)/(p^2 - 1), 0], m == 1 || m == 4, Sum[(k + 1)*(e - k + 1)*p^k, {k, 0, e}]]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, May 13 2022 *)
  • PARI
    {a(n)=local(A); if(n<1, 0, A=direuler(p=2,n,1/(1-X)/(1-kronecker(5,p)*X)); sumdiv(n,d,A[d]*d*A[n/d]))} /* Michael Somos, Jun 06 2005 */
    
  • PARI
    pf(p, r) = {if (p==5, (5^(r+1) -1)/4, if (((p % 5) == 2) || ((p % 5) == 3), if (!(r % 2), (p^(r+2) - 1)/(p^2-1), 0), if (((p % 5) == 1) || ((p % 5) == 4), sum(k=0, r, (k+1)*(r-k+1)*p^k))););}
    a(n) = {my(f = factor(n)); prod(i=1, #f~, pf(f[i, 1], f[i, 2]));} \\ Michel Marcus, Mar 03 2014

Formula

Multiplicative with a(p^e) = (5^(e + 1) - 1)/4 if p = 5, (p^(e + 2) - 1)/(p^2 - 1) or 0 if p == 2 or 3 (mod 5) and e is even or odd, respectively, and Sum_{k=0..e} (k + 1)*(e - k + 1)*p^k if p == 1 or 4 (mod 5). - Amiram Eldar, May 13 2022

A249076 a(n) = (n*(n+1))^6.

Original entry on oeis.org

0, 64, 46656, 2985984, 64000000, 729000000, 5489031744, 30840979456, 139314069504, 531441000000, 1771561000000, 5289852801024, 14412774445056, 36343632130624, 85766121000000, 191102976000000, 404961208827904, 820972403643456, 1600135042849344, 3010936384000000, 5489031744000000
Offset: 0

Views

Author

Jiwoo Lee, Oct 20 2014

Keywords

Crossrefs

Cf. A059978; A002378: n*(n+1); A035282: n^2 *(n+1)^2; A060459: n^3 *(n+1)^3; A248619: n^4 *(n+1)^4;

Programs

  • Magma
    [(n*(n+1))^6: n in [0..30]];
    
  • Maple
    [ seq(n^6*(n+1)^6, n = 0..100) ];
  • Mathematica
    Table[(n (n + 1))^6, {n, 0, 70}] (* or *)
    CoefficientList[Series[64*x*(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, {x, 0, 30}], x]
  • PARI
    a(n)=(n*(n+1))^6 \\ Charles R Greathouse IV, Oct 21 2014

Formula

a(n) = A002378(n)^6.
a(n) = 64*A059978(n) for n>0.
G.f.: 64*x*(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. [corrected by Georg Fischer, May 10 2019]
Sum_{n>=1} 1/a(n) = -462 + 42*Pi^2 + 7*Pi^4/15 + 2*Pi^6/945. - Vaclav Kotesovec, Sep 25 2019

Extensions

Incorrect term corrected by Colin Barker, Oct 21 2014
Terms a(21) and beyond corrected by Andrew Howroyd, Feb 22 2018

A035111 Numerators in expansion of a certain Dirichlet series.

Original entry on oeis.org

1, 5, 6, 10, 24, 20, 40, 30, 30, 60, 64, 50, 84, 120, 60, 50, 144, 120, 124, 80, 144, 200, 160, 120, 90, 180, 240, 240, 150, 204, 220, 300, 408, 320, 150, 264, 280, 200, 360, 300, 304, 384, 420, 170, 400, 480, 360, 300, 364, 384, 250, 400, 504, 960, 424, 720, 300
Offset: 0

Views

Author

Keywords

Comments

This is the SO(3) case, whereas the SO(4) case is reported in A078473 and A035282. [From R. J. Mathar, Jul 16 2010]

Extensions

More terms from R. J. Mathar, Jul 16 2010
Showing 1-4 of 4 results.