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 1-6 of 6 results.

A027860 a(n) = (-tau(n) + sigma_11(n)) / 691, where tau is Ramanujan's tau (A000594), sigma_11(n) = Sum_{ d divides n } d^11 (A013959).

Original entry on oeis.org

0, 3, 256, 6075, 70656, 525300, 2861568, 12437115, 45414400, 144788634, 412896000, 1075797268, 2593575936, 5863302600, 12517805568, 25471460475, 49597544448, 93053764671, 168582124800, 296526859818, 506916761600, 846025507836, 1378885295616, 2203231674900
Offset: 1

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Author

Keywords

Comments

It appears that this sequence is strictly increasing. - Jianing Song, Aug 05 2018

References

  • "Number Theory I", vol. 49 of the Encyc. of Math. Sci.

Crossrefs

Similar sequences: A281788, A281876, A281928, A281956, A281979.

Programs

  • Macsyma
    (sum(n^11*q^n/(1-q^n), n,1,inf)-q*prod(1-q^n,n,1,inf)^24)/691; taylor(%,q,0,24);
    
  • Maple
    N:= 100: # to get a(1) to a(N)
    S:= series(q*mul((1-q^k)^24,k=1..N),q,N+1):
    seq((-coeff(S,q,n) + add(d^11, d = numtheory:-divisors(n)))/691, n=1..N); # Robert Israel, Nov 12 2014
  • Mathematica
    {0}~Join~Array[(-RamanujanTau@ # + DivisorSigma[11, #])/691 &, 24] (* Michael De Vlieger, Aug 05 2018 *)
  • PARI
    a(n) = (sigma(n, 11) - polcoeff( x * eta(x + x * O(x^n))^24, n))/691; \\ for n>0; Michel Marcus, Nov 12 2014
    
  • Sage
    def A027860List(len):
        r = list(delta_qexp(len+1))
        return [(sigma(n, 11) - r[n])/691 for n in (1..len)]
    A027860List(24) # Peter Luschny, Aug 20 2018

Formula

a(n) = (A013959(n) - A000594(n))/691. - Michel Marcus, Nov 12 2014

Extensions

More terms from Michel Marcus, Nov 12 2014

A281788 a(n) = (A013967(n) - A037945(n))/174611.

Original entry on oeis.org

0, 3, 6656, 1574235, 109234176, 3489819540, 65281655808, 825351571995, 7736349470720, 57270269768634, 350259092774400, 1829670576438068, 8372440970643456, 34226453991167880, 126958657929489408, 432721923827171355, 1369171676955783168, 4056082931864408991, 11330441127202890240, 30026115193307387658, 75874353000273633280, 183636989491548765276
Offset: 1

Views

Author

Seiichi Manyama, Feb 03 2017

Keywords

Examples

			a(1) = (1 - 1)/174611 = 0.
a(2) = (524289 - 456)/174611 = 3.
a(3) = (1162261468 - 50652)/174611 = 6656.
		

Crossrefs

A281876 a(n) = (A013963(n) - A027364(n))/3617.

Original entry on oeis.org

0, 9, 3968, 296865, 8437248, 129997260, 1312568064, 9727799265, 56923182080, 276480648702, 1154893046400, 4259743681004, 14151477247488, 43011568291320, 121065502097664, 318760489739745, 791380439553024, 1865315725321293, 4197159808767360, 9059718006875214
Offset: 1

Views

Author

Seiichi Manyama, Feb 01 2017

Keywords

Examples

			a(1) = (1 - 1)/3617 = 0.
a(2) = (32769 - 216)/3617 = 9.
a(3) = (14348908 - (-3348))/3617 = 3968.
		

Crossrefs

A281928 a(n) = (A013965(n) - A037944(n))/43867.

Original entry on oeis.org

0, 3, 2944, 391635, 17392128, 385866060, 5303086848, 51332824275, 380176030720, 2279635315794, 11522261136000, 50576242992268, 197196432781824, 695091512105880, 2246019242126592, 6728295917456595, 18857917384178688, 49830812542200039
Offset: 1

Views

Author

Seiichi Manyama, Feb 02 2017

Keywords

Examples

			a(1) = (1 - 1)/43867 = 0.
a(2) = (131073 - (-528))/43867 = 3.
a(3) = (129140164 - (-4284))/43867 = 2944.
		

Crossrefs

A282047 Coefficients in q-expansion of E_4^4*E_6, where E_4 and E_6 are respectively the Eisenstein series A004009 and A013973.

Original entry on oeis.org

1, 456, -146232, -133082976, -32170154808, -3378441902544, -155862776255328, -3969266446940352, -65538944782146360, -777506848190979672, -7105808014591457232, -52584752452485047328, -326903300701760852832, -1755591608260377411216
Offset: 0

Views

Author

Seiichi Manyama, Feb 05 2017

Keywords

References

  • G. E. Andrews and B. C. Berndt, Ramanujan's lost notebook, Part III, Springer, New York, 2012, See p. 208.

Crossrefs

Cf. A004009 (E_4), A013973 (E_6), A013974 (E_4*E_6 = E_10), A058550 (E_4^2*E_6 = E_14), A282000 (E_4^3*E_6), this sequence (E_4^4*E_6), A282048 (E_4^5*E_6).

Programs

  • Mathematica
    terms = 14;
    E4[x_] = 1 + 240*Sum[k^3*x^k/(1 - x^k), {k, 1, terms}];
    E6[x_] = 1 - 504*Sum[k^5*x^k/(1 - x^k), {k, 1, terms}];
    E4[x]^4*E6[x] + O[x]^terms // CoefficientList[#, x]& (* Jean-François Alcover, Feb 26 2018 *)

Formula

-552 * A013969(n) = 77683 * a(n) - 35424000 * A037946(n) for n > 0.

A281979 a(n) = (A281959(n) - A037947(n))/657931.

Original entry on oeis.org

0, 51, 1287808, 1711273635, 452970333696, 43211657266860, 2038311950075136, 57420813107839395, 1091144797392901120, 15199162675148592018, 164678453263146595200, 1449942615368630353516, 10725152052216567264768, 68394401763888606334680
Offset: 1

Views

Author

Seiichi Manyama, Feb 04 2017

Keywords

Examples

			a(1) = (1 - 1)/657931 = 0.
a(2) = (33554433 - (-48))/657931 = 51.
a(3) = (847288609444 - (-195804))/657931 = 1287808.
		

Crossrefs

Showing 1-6 of 6 results.