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.

A192731 Euler transform is 1 / (q j(q)) where j is j-function (A000521).

Original entry on oeis.org

-744, 80256, -12288744, 2126816256, -392642298600, 75506620496256, -14935073808384744, 3015675387953504256, -618587635244888064744, 128473308888136855075200, -26951900214112779571200744
Offset: 1

Views

Author

Michael Somos, Jul 08 2011

Keywords

Examples

			From _Seiichi Manyama_, Jun 18 2017: (Start)
a(1) = (1/1) * A008683(1/1) * A288261(1) = (1/1) * (-744) = -744,
a(2) = (1/2) * (A008683(2/1) * A288261(1) + A008683(2/2) * A288261(2)) = (1/2) * (744 + 159768) = 80256. (End)
		

Crossrefs

Programs

  • PARI
    {a(n) = local(A, S); if( n<1, 0, A = 1 + x * O(x^n); S = x * ellj( x * A ); for( k = 1, n-1, S *= (A - x^k) ^ polcoeff( S, k)); - polcoeff( S, n))}

Formula

1 / (q j(q)) = Product_{k>0} (1 - x^k)^-a(k).
a(n) = 3*(A110163(n) - 8) = (1/n) * Sum_{d|n} A008683(n/d) * A288261(d). - Seiichi Manyama, Jun 18 2017
a(n) ~ (-1)^n * 3*exp(Pi*sqrt(3)*n) / n. - Vaclav Kotesovec, Mar 24 2018

A304020 Coefficients of (q*(j(q)-744))^(1/4) where j(q) is the elliptic modular invariant.

Original entry on oeis.org

1, 0, 49221, 5373440, -3417985269, -788396806656, 342234419865236, 132462307415526912, -36238724753334630039, -22802599804762047656960, 3430044089325166785294348, 3917150794938668128412249088, -180732068045239143713224620097
Offset: 0

Views

Author

Seiichi Manyama, Jun 08 2018

Keywords

Crossrefs

(q*(j(q)-744))^(k/4): A305699 (k=-4), A305698 (k=-2), A305696 (k=-1), this sequence (k=1), A305697 (k=2).
Cf. A000521 (j), A014708 (j-744), A106203, A106205, A302407.

Programs

  • Mathematica
    CoefficientList[Series[((2^16 + x*QPochhammer[-1, x]^24)^3/(2*QPochhammer[-1, x])^24 - 744*x)^(1/4), {x, 0, 15}], x] (* Vaclav Kotesovec, Jun 09 2018 *)

Formula

G.f.: Product_{k>0} (1 - x^k)^(-A302407(k)/4).

A305696 Coefficients of (q*(j(q)-744))^(-1/4) where j(q) is the elliptic modular invariant.

Original entry on oeis.org

1, 0, -49221, -5373440, 5840692110, 1317368987136, -769081921703395, -285861152927176704, 99587019847435059600, 58472021328782000084480, -11456674101843809483255526, -11455351916487867258761894400, 892125673948866841204086469705
Offset: 0

Views

Author

Seiichi Manyama, Jun 08 2018

Keywords

Crossrefs

(q*(j(q)-744))^(k/4): A305699 (k=-4), A305698 (k=-2), this sequence (k=-1), A304020 (k=1), A305697 (k=2).
Cf. A000521 (j), A014708 (j-744), A289397, A289416, A302407.

Programs

  • Mathematica
    CoefficientList[Series[((2^16 + x*QPochhammer[-1, x]^24)^3/(2*QPochhammer[-1, x])^24 - 744*x)^(-1/4), {x, 0, 15}], x] (* Vaclav Kotesovec, Jun 09 2018 *)

Formula

G.f.: Product_{k>0} (1 - x^k)^(A302407(k)/4).

A305757 Inverse Euler transform of q*(j-720) where j is j-function (A000521).

Original entry on oeis.org

24, 196584, 16773144, -18919981056, -3292295086056, 2312547886368744, 640457437563740184, -302667453389051314176, -123005476312830648176616, 39529719620247267255853032, 23306082528463942764630528024, -4849033309391159571741461446656
Offset: 1

Views

Author

Seiichi Manyama, Jun 10 2018

Keywords

Comments

(Conjecture) Let {b_n} = inverse Euler transform of (q*(j+144*k)). b_n is a multiple of 24.

Examples

			(1-x)^(-24) * (1-x^2)^(-196584) * (1-x^3)^(-16773144) * (1-x^4)^18919981056 * ... = 1 + 24*x + 196884*x^2 + 21493760*x^3 + 864299970*x^4 + ... .
		

Crossrefs

Inverse Euler transform of q*(j+144*k): (-1)*A192731 (k=0), this sequence (k=-5), (-1)*A289061 (k=-12).
Cf. A000521, A007240 (j-720), A302407, A305756.

Formula

q*(j-720) = Product_{k>0} (1 - x^k)^(-a(k)).
Showing 1-4 of 4 results.