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.

A205968 a(n) = Fibonacci(n)*A008655(n) for n >= 1, with a(0)=1, where A008655 lists the coefficients in (theta_3(x)*theta_3(3*x) + theta_2(x)*theta_2(3*x))^4.

Original entry on oeis.org

1, 24, 216, 1776, 5256, 15120, 63936, 107328, 294840, 823344, 1496880, 2845152, 9334656, 12291216, 28012608, 68251680, 110883528, 188343792, 563167296, 688359840, 1493387280, 3343696512, 5095667232, 8368761024, 24087248640, 28361250600, 57633511824, 128471514096
Offset: 0

Views

Author

Paul D. Hanna, Feb 04 2012

Keywords

Comments

Compare g.f. to the Lambert series of A008655:
1 + Sum_{n>=1} 24*n^3*x^n/(1-x^n) + 8*(3*n)^3*x^(3*n)/(1-x^(3*n)).

Examples

			G.f.: A(x) = 1 + 24*x + 216*x^2 + 1776*x^3 + 5256*x^4 + 15120*x^5 + ...
where A(x) = 1 + 1*24*x + 1*216*x^2 + 2*888*x^3 + 3*1752*x^4 + 5*3024*x^5 + ... + Fibonacci(n)*A008655(n)*x^n + ...
		

Crossrefs

Cf. A209448 (Pell variant).

Programs

  • Mathematica
    A008655 := CoefficientList[Series[((EllipticTheta[3, 0, q]^3 + EllipticTheta[3, Pi/3, q]^3 + EllipticTheta[3, 2 Pi/3, q]^3)^4/(3* EllipticTheta[3, 0, q^3])^4), {q, 0, 250}], q]; b := Table[A008655[[n]], {n, 1, 120}][[1 ;; ;; 2]]; Join[{1}, Table[Fibonacci[n]*b[[n + 1]], {n, 1, 50}]] (* G. C. Greubel, Jul 16 2018 *)
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
    {a(n)=polcoeff(1 + sum(m=1,n, 24*fibonacci(m)*m^3*x^m/(1-Lucas(m)*x^m+(-1)^m*x^(2*m) +x*O(x^n)) + 8*fibonacci(3*m)*(3*m)^3*x^(3*m)/(1-Lucas(3*m)*x^(3*m)+(-1)^m*x^(6*m) +x*O(x^n)) ),n)}
    for(n=0,40,print1(a(n),", "))

Formula

G.f.: 1 + Sum_{n>=1} 24*Fibonacci(n)*n^3*x^n/(1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) + 8*Fibonacci(3*n)*(3*n)^3*x^(3*n)/(1 - Lucas(3*n)*x^(3*n) + (-1)^n*x^(6*n)).

A209448 a(n) = Pell(n)*A008655(n) for n>=1, with a(0)=1, where A008655 lists the coefficients in (theta_3(x)*theta_3(3*x)+theta_2(x)*theta_2(3*x))^4.

Original entry on oeis.org

1, 24, 432, 4440, 21024, 87696, 559440, 1395264, 5728320, 23852760, 64719648, 183528288, 898460640, 1765134672, 6002425728, 21820957200, 52895150208, 134056553904, 598084104240, 1090757945760, 3530801969856, 11795485116480, 26821191064896, 65724336729792
Offset: 0

Views

Author

Paul D. Hanna, Mar 10 2012

Keywords

Comments

Compare g.f. to the Lambert series of A008655:
1 + Sum_{n>=1} 24*n^3*x^n/(1-x^n) + 8*(3*n)^3*x^(3*n)/(1-x^(3*n)).

Examples

			G.f.: A(x) = 1 + 24*x + 432*x^2 + 4440*x^3 + 21024*x^4 + 87696*x^5 +...
where A(x) = 1 + 1*24*x + 2*216*x^2 + 5*888*x^3 + 12*1752*x^4 + 29*3024*x^5 +...+ Pell(n)*A008655(n)*x^n +...
		

Crossrefs

Programs

  • Mathematica
    A008655[n_]:= SeriesCoefficient[((EllipticTheta[3, 0, q]^3 + EllipticTheta[3, Pi/3, q]^3 + EllipticTheta[3, 2 Pi/3, q]^3)^4/(3* EllipticTheta[3, 0, q^3])^4), {q, 0, n}]; b:= Table[A008655[n], {n, 0, 102}][[1 ;; ;; 2]]; Join[{1}, Table[Fibonacci[n, 2]*b[[n + 1]], {n, 1, 50}]] (* G. C. Greubel, Jan 26 2018 *)
  • PARI
    {Pell(n)=polcoeff(x/(1-2*x-x^2+x*O(x^n)),n)}
    {A002203(n)=Pell(n-1)+Pell(n+1)}
    {a(n)=polcoeff(1 + sum(m=1,n, 24*Pell(m)*m^3*x^m/(1-A002203(m)*x^m+(-1)^m*x^(2*m) +x*O(x^n)) + 8*Pell(3*m)*(3*m)^3*x^(3*m)/(1-A002203(3*m)*x^(3*m)+(-1)^m*x^(6*m) +x*O(x^n))  ),n)}
    for(n=0,40,print1(a(n),", "))

Formula

G.f.: 1 + Sum_{n>=1} 24*Pell(n)*n^3*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) + 8*Pell(3*n)*(3*n)^3*x^(3*n)/(1 - A002203(3*n)*x^(3*n) + (-1)^n*x^(6*n)), where A002203(n) = Pell(n-1) + Pell(n+1).

A341306 Fourier coefficients of the modular form F_{3A}^8.

Original entry on oeis.org

1, 48, 1008, 12144, 92784, 473760, 1706544, 4818048, 12317040, 29078832, 59093280, 114031296, 219429552, 367093536, 621859968, 1037221920, 1583864688, 2403178848, 3747390192, 5232056640, 7550261280, 10938344064, 14714951616, 19930041216, 28075097520, 35731471440
Offset: 0

Views

Author

N. J. A. Sloane, Feb 14 2021

Keywords

Crossrefs

Cf. A008655.

Programs

Extensions

Terms a(5) and beyond from R. J. Mathar, Feb 22 2021

A341556 Fourier coefficients of the modular form F_{3A}^12.

Original entry on oeis.org

1, 72, 2376, 47592, 646344, 6305904, 45821160, 255215808, 1125009864, 4097478600, 12975540336, 37101202848, 96867424872, 232791251760, 526183909056, 1128351033648, 2286328733640, 4451427831312, 8386379869896, 15130456297056, 26613241744752, 45684436953024, 75935115663264
Offset: 0

Views

Author

Robert C. Lyons, Feb 14 2021

Keywords

Crossrefs

Formula

Convolution cube of A008655. - Georg Fischer, Mar 30 2023

Extensions

More terms from Georg Fischer, Mar 30 2023

A341557 Fourier coefficients of the modular form (1/t_{3A}) * F_{3A}^12.

Original entry on oeis.org

0, 1, 30, 333, 1444, -570, -21114, -22576, 121848, 64233, -276300, 589260, -1198764, 133766, -957216, 2920590, 2491792, -1616958, 1647054, -5312428, -14819880, -4158576, 20300904, 16879848, 19051416, -22583225, 38165172, -81066987, -47716288, 66118494, 370980, -51834232
Offset: 0

Views

Author

Robert C. Lyons, Feb 14 2021

Keywords

Crossrefs

Formula

Convolution product of 1/A030197 and A008655^3. - Georg Fischer, Mar 31 2023

Extensions

More terms from Georg Fischer, Mar 31 2023

A341561 Fourier coefficients of the modular form (1/t_{3A}) * F_{3A}^16.

Original entry on oeis.org

0, 1, 54, 1269, 16804, 134406, 628398, 1311968, -1701864, -14345991, -16443324, 25426764, 11246580, 16601078, 505866816, -113853762, -1326884336, 1507092642, -3873575034, 100819028, 2685180888, 6885133920, -20849400, 10111254408, -10371867912, -412371305, -58625773596
Offset: 0

Views

Author

Robert C. Lyons, Feb 14 2021

Keywords

Crossrefs

Programs

  • Sage
    def a(n):
        if n==0: return 0
        eta = x^(1/24)*product([(1 - x^k) for k in range(1, n)])
        t3A = ((eta/eta(x=x^3))^12 + 27)^2/(eta/eta(x=x^3))^12
        F3A = sum([rising_factorial(1/6, k)*rising_factorial(1/3, k)/
          (rising_factorial(1,k)^2)*(108/t3A)^k for k in range(n)])
        f = F3A^16/t3A
        return f.taylor(x,0,n).coefficients()[n-1][0]  # Robin Visser, Jul 23 2023

Formula

Convolution product of 1/A030197 and A008655^4. - Georg Fischer, Mar 30 2023

Extensions

More terms from Georg Fischer, Mar 30 2023
Showing 1-6 of 6 results.