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.

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A204270 a(n) = tau(n)*Pell(n), where tau(n) = A000005(n), the number of divisors of n.

Original entry on oeis.org

1, 4, 10, 36, 58, 280, 338, 1632, 2955, 9512, 11482, 83160, 66922, 323128, 780100, 2354160, 2273378, 16465260, 13250218, 95966568, 154455860, 372889432, 450117362, 4346717760, 3935214363, 12667263848, 30581480180, 110745336312, 89120964298
Offset: 1

Views

Author

Paul D. Hanna, Jan 14 2012

Keywords

Comments

Compare g.f. to the Lambert series identity: Sum_{n>=1} x^n/(1-x^n) = Sum_{n>=1} tau(n)*x^n.
Related identities:
(1) Sum_{n>=1} n^k*Pell(n)*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) = Sum_{n>=1} sigma_{k}(n)*Pell(n)*x^n for k>=0.
(2) Sum_{n>=1} phi(n)*Pell(n)*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) = Sum_{n>=1} n*Pell(n)*x^n.
(3) Sum_{n>=1} moebius(n)*Pell(n)*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) = x.
(4) Sum_{n>=1} lambda(n)*Pell(n)*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) = Sum_{n>=1} Pell(n^2)*x^(n^2).

Examples

			G.f.: A(x) = 1 + 4*x + 10*x^2 + 36*x^3 + 58*x^4 + 280*x^5 + 338*x^6 +...
where A(x) = x/(1-2*x-x^2) + 2*x^2/(1-6*x^2+x^4) + 5*x^3/(1-14*x^3-x^6) + 12*x^4/(1-34*x^4+x^8) + 29*x^5/(1-82*x^5-x^10) + 70*x^6/(1-198*x^6+x^12) +...+ Pell(n)*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) +...

Links

Crossrefs

Cf. A203847, A204271, A204272, A204273, A204274, A204275, A000005 (tau), A002203, A000045.

Programs

  • Mathematica
    Table[DivisorSigma[0, n] Fibonacci[n, 2], {n, 1, 50}] (* G. C. Greubel, Jan 05 2018 *)
  • PARI
    /* Subroutines used in PARI programs below: */
{Pell(n)=polcoeff(x/(1-2*x-x^2+x*O(x^n)), n)}
{A002203(n)=polcoeff(2*(1-x)/(1-2*x-x^2+x*O(x^n)), n)}
  • PARI
    {a(n)=sigma(n,0)*Pell(n)}
  • PARI
    {a(n)=polcoeff(sum(m=1,n,Pell(m)*x^m/(1-A002203(m)*x^m+(-1)^m*x^(2*m)+x*O(x^n))),n)}

Formula

G.f.: Sum_{n>=1} Pell(n)*x^n/(1 - A002203(n)*x^n + (-1)^n*x^(2*n)) = Sum_{n>=1} tau(n)*Pell(n)*x^n, where Pell(n) = A000129(n) and A002203 is the companion Pell numbers.

A205966 a(n) = Fibonacci(n)*A004016(n) for n>=1, with a(0)=1, where A004016(n) is the number of integer solutions (x,y) to x^2 + x*y + y^2 = n.

Original entry on oeis.org

1, 6, 0, 12, 18, 0, 0, 156, 0, 204, 0, 0, 864, 2796, 0, 0, 5922, 0, 0, 50172, 0, 131352, 0, 0, 0, 450150, 0, 1178508, 3813732, 0, 0, 16155228, 0, 0, 0, 0, 89582112, 289893804, 0, 758951832, 0, 0, 0, 5201933244, 0, 0, 0, 0, 28845161856, 140017356882, 0, 0
Offset: 0

Views

Author

Paul D. Hanna, Feb 03 2012

Keywords

Comments

Compare g.f. to the Lambert series of A004016: 1 + 6*Sum_{n>=1} Kronecker(n,3)*x^n/(1 - x^n).

Examples

			G.f.: A(x) = 1 + 6*x + 12*x^3 + 18*x^4 + 156*x^7 + 204*x^9 + 864*x^12 +...
where A(x) = 1 + 1*6*x + 2*6*x^3 + 3*6*x^4 + 13*12*x^7 + 34*6*x^9 + 144*6*x^12 +...+ Fibonacci(n)*A004016(n)*x^n +...
The g.f. is also given by the identity:
A(x) = 1 + 6*( 1*x/(1-x-x^2) - 1*x^2/(1-3*x^2+x^4) + 3*x^4/(1-7*x^4+x^8) - 5*x^5/(1-11*x^5-x^10) + 13*x^7/(1-29*x^7-x^14) - 21*x^8/(1-47*x^8-x^16) +...).
The values of the symbol Kronecker(n,3) repeat [1,-1,0, ...].

Links

Crossrefs

Cf. A004016, A205965, A205967, A203847, A000204 (Lucas).
Cf. A209446 (Pell variant).

Programs

  • Mathematica
    A004016[n_] := SeriesCoefficient[(QPochhammer[q]^3 + 9 q QPochhammer[q^9]^3)/QPochhammer[q^3], {q, 0, n}]; Join[{1}, Table[Fibonacci[n]*b[n], {n,1,50}]] (* G. C. Greubel, Mar 05 2017 *)
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(1 + 6*sum(m=1,n,kronecker(m,3)*fibonacci(m)*x^m/(1-Lucas(m)*x^m+(-1)^m*x^(2*m) +x*O(x^n))),n)}
for(n=0,60,print1(a(n),", "))

Formula

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

A205967 a(n) = Fibonacci(n)*A008653(n) for n>=1, with a(0)=1, where A008653 is the theta series of direct sum of 2 copies of hexagonal lattice.

Original entry on oeis.org

1, 12, 36, 24, 252, 360, 288, 1248, 3780, 408, 11880, 12816, 12096, 39144, 108576, 43920, 367164, 344952, 93024, 1003440, 3409560, 1050816, 7651152, 8253216, 8346240, 27909300, 61182072, 2357016, 213568992, 185122440, 179720640, 516967296, 1646801604, 507539232
Offset: 0

Views

Author

Paul D. Hanna, Feb 04 2012

Keywords

Comments

Compare g.f. to the Lambert series of A008653: 1 + 12*Sum_{n>=1} Chi(n,3)*n*x^n/(1-x^n).
Here Chi(n,3) = principal Dirichlet character of n modulo 3.

Examples

			G.f.: A(x) = 1 + 12*x + 36*x^2 + 24*x^3 + 252*x^4 + 360*x^5 + 288*x^6 +...
where A(x) = 1 + 1*12*x + 1*36*x^2 + 2*12*x^3 + 3*84*x^4 + 5*72*x^5 + 8*36*x^6 +...+ Fibonacci(n)*A008653(n)*x^n +...
The g.f. is also given by the identity:
A(x) = 1 + 12*( 1*1*x/(1-x-x^2) + 1*2*x^2/(1-3*x^2+x^4) + 3*4*x^4/(1-7*x^4+x^8) + 5*5*x^5/(1-11*x^5-x^10) + 13*7*x^7/(1-29*x^7-x^14) + 21*8*x^8/(1-47*x^8-x^16)  +...).
The values of the Dirichlet character Chi(n,3) repeat [1,1,0, ...].

Links

Crossrefs

Cf. A008653, A205966, A205968, A203847, A000204 (Lucas).
Cf. A209447 (Pell variant).

Programs

  • Mathematica
    terms = 34; s = 1 + 12*Sum[Fibonacci[n]*KroneckerSymbol[n, 3]^2*n*(x^n/(1 - LucasL[n]*x^n + (-1)^n*x^(2*n))), {n, 1, terms}] + O[x]^terms; CoefficientList[s, x] (* Jean-François Alcover, Jul 05 2017 *)
b[n_] := If[n < 1, Boole[n == 0], 12 Sum[If[Mod[d, 3] > 0, d, 0], {d, Divisors@n}]]; Table[If[n == 0, 1, b[n]*Fibonacci[n]], {n, 0, 50}] (* G. C. Greubel, Jul 17 2018 *)
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(1 + 12*sum(m=1,n,fibonacci(m)*kronecker(m,3)^2*m*x^m/(1-Lucas(m)*x^m+(-1)^m*x^(2*m) +x*O(x^n))),n)}
for(n=0,50,print1(a(n),", "))

Formula

G.f.: 1 + 12*Sum_{n>=1} Fibonacci(n)*Chi(n,3)*n*x^n/(1 - Lucas(n)*x^n + (-1)^n*x^(2*n)).

A205969 a(n) = Fibonacci(n)*A113973(n) for n>=1, with a(0)=1, where A113973 lists the coefficients in phi(x^3)^3/phi(x) and phi() is a Ramanujan theta function.

Original entry on oeis.org

1, -2, 4, -4, 6, 0, 32, -52, 84, -68, 0, 0, 288, -932, 3016, 0, 1974, 0, 10336, -16724, 0, -43784, 0, 0, 185472, -150050, 971144, -392836, 1271244, 0, 0, -5385076, 8713236, 0, 0, 0, 29860704, -96631268, 312705352, -252983944, 0, 0, 2143314368, -1733977748, 0
Offset: 0

Views

Author

Paul D. Hanna, Feb 04 2012

Keywords

Comments

Compare g.f. to the Lambert series of A113973: 1 - 2*Sum_{n>=1} Kronecker(n,3)*x^n/(1 - (-x)^n).

Examples

			G.f.: A(x) = 1 - 2*x + 4*x^2 - 4*x^3 + 6*x^4 + 32*x^6 - 52*x^7 + 84*x^8 +...
where A(x) = 1 - 1*2*x + 1*4*x^2 - 2*2*x^3 + 3*2*x^4 + 8*4*x^6 - 13*4*x^7 + 21*4*x^8 +...+ Fibonacci(n)*A113973(n)*x^n +...
The g.f. is also given by the identity:
A(x) = 1 - 2*( 1*x/(1+x-x^2) - 1*x^2/(1-3*x^2+x^4) + 3*x^4/(1-7*x^4+x^8) - 5*x^5/(1+11*x^5-x^10) + 13*x^7/(1+29*x^7-x^14) - 21*x^8/(1-47*x^8+x^16) +...).
The values of the symbol Kronecker(n,3) repeat [1,-1,0, ...].

Links

Crossrefs

Cf. A113973, A205966, A205968, A205970, A203847, A000204 (Lucas).
Cf. A209449 (Pell variant).

Programs

  • Mathematica
    A113973:= CoefficientList[Series[EllipticTheta[3, q^3]^3/EllipticTheta[3, 0, q], {q, 0, 75}], q]; Table[If[n == 1, 1, Fibonacci[n-1]*A113973[[n]] ], {n, 1, 50}] (* G. C. Greubel, Jul 17 2018 *)
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(1 - 2*sum(m=1,n,fibonacci(m)*kronecker(m,3)*x^m/(1-Lucas(m)*(-x)^m+(-1)^m*x^(2*m) +x*O(x^n))),n)}
for(n=0,60,print1(a(n),", "))

Formula

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

A203848 a(n) = sigma(n)*Fibonacci(n), where sigma(n) = A000203(n), the sum of divisors of n.

Original entry on oeis.org

1, 3, 8, 21, 30, 96, 104, 315, 442, 990, 1068, 4032, 3262, 9048, 14640, 30597, 28746, 100776, 83620, 284130, 350272, 637596, 687768, 2782080, 2325775, 5098506, 7856720, 17797416, 15426870, 59906880, 43080608, 137233467, 169179744, 307955898, 442918320, 1358662032
Offset: 1

Views

Author

Paul D. Hanna, Jan 12 2012

Keywords

Comments

Compare g.f. to the Lambert series identity: Sum_{n>=1} n*x^n/(1-x^n) = Sum_{n>=1} sigma(n)*x^n.

Examples

			G.f.: A(x) = x + 3*x^2 + 8*x^3 + 21*x^4 + 30*x^5 + 96*x^6 + 104*x^7 +...
where A(x) = x/(1-x-x^2) + 2*1*x^2/(1-3*x^2+x^4) + 3*2*x^3/(1-4*x^3-x^6) + 4*3*x^4/(1-7*x^4+x^8) + 5*5*x^5/(1-11*x^5-x^10) + 6*8*x^6/(1-18*x^6+x^12) +...+ n*fibonacci(n)*x^n/(1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) +...

Links

Crossrefs

Cf. A203847, A203849, A203838, A000203 (sigma), A000204 (Lucas), A000045.

Programs

  • Magma
    [DivisorSigma(1, n)*Fibonacci(n): n in [1..40]]; // Vincenzo Librandi, Aug 12 2016
  • Mathematica
    Table[DivisorSigma[1, n] Fibonacci[n], {n, 40}] (* Wesley Ivan Hurt, Aug 10 2016 *)
  • PARI
    {a(n)=sigma(n)*fibonacci(n)}
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(sum(m=1,n,m*fibonacci(m)*x^m/(1-Lucas(m)*x^m+(-1)^m*x^(2*m)+x*O(x^n))),n)}

Formula

G.f.: Sum_{n>=1} n*fibonacci(n)*x^n/(1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) = Sum_{n>=1} sigma(n)*fibonacci(n)*x^n, where Lucas(n) = A000204(n).

A203849 a(n) = sigma_2(n)*Fibonacci(n), where sigma_2(n) = A001157(n), the sum of squares of divisors of n.

Original entry on oeis.org

1, 5, 20, 63, 130, 400, 650, 1785, 3094, 7150, 10858, 30240, 39610, 94250, 158600, 336567, 463130, 1175720, 1513522, 3693690, 5473000, 10803710, 15188210, 39412800, 48841275, 103184050, 161062760, 333701550, 432980818, 1081652000, 1295110778, 2973391785, 4299985160
Offset: 1

Views

Author

Paul D. Hanna, Jan 12 2012

Keywords

Comments

Compare g.f. to the Lambert series identity: Sum_{n>=1} n^2*x^n/(1-x^n) = Sum_{n>=1} sigma_2(n)*x^n.

Examples

			G.f.: A(x) = x + 5*x^2 + 20*x^3 + 63*x^4 + 130*x^5 + 400*x^6 + 650*x^7 +...
where A(x) = x/(1-x-x^2) + 2^2*1*x^2/(1-3*x^2+x^4) + 3^2*2*x^3/(1-4*x^3-x^6) + 4^2*3*x^4/(1-7*x^4+x^8) + 5^2*5*x^5/(1-11*x^5-x^10) + 6^2*8*x^6/(1-18*x^6+x^12) +...+ n^2*fibonacci(n)*x^n/(1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) +...

Links

Crossrefs

Cf. A203847, A203848, A203838, A001157 (sigma_2), A000204 (Lucas), A000045.

Programs

  • Mathematica
    Table[DivisorSigma[2, n]*Fibonacci[n], {n, 50}] (* G. C. Greubel, Jul 17 2018 *)
  • PARI
    {a(n)=sigma(n,2)*fibonacci(n)}
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(sum(m=1,n,m^2*fibonacci(m)*x^m/(1-Lucas(m)*x^m+(-1)^m*x^(2*m)+x*O(x^n))),n)}

Formula

G.f.: Sum_{n>=1} n^2*fibonacci(n)*x^n/(1 - Lucas(n)*x^n + (-1)^n*x^(2*n)) = Sum_{n>=1} sigma_2(n)*fibonacci(n)*x^n, where Lucas(n) = A000204(n).

A205507 a(n) = Fibonacci(n) * A004018(n) for n>=1 with a(0)=1, where A004018(n) is the number of ways of writing n as a sum of 2 squares.

Original entry on oeis.org

1, 4, 4, 0, 12, 40, 0, 0, 84, 136, 440, 0, 0, 1864, 0, 0, 3948, 12776, 10336, 0, 54120, 0, 0, 0, 0, 900300, 971144, 0, 0, 4113832, 0, 0, 8713236, 0, 45623096, 0, 59721408, 193262536, 0, 0, 818673240, 1324641128, 0, 0, 0, 9079225360, 0, 0, 0, 31114968196
Offset: 0

Views

Author

Paul D. Hanna, Jan 28 2012

Keywords

Comments

Compare to the g.f. of A004018 given by the Lambert series identity:
1 + 4*Sum_{n>=0} (-1)^n*x^(2*n+1)/(1 - x^(2*n+1)) = (1 + 2*Sum_{n>=1} x^(n^2))^2.

Examples

			G.f.: A(x) = 1 + 4*x + 4*x^2 + 12*x^4 + 40*x^5 + 84*x^8 + 136*x^9 + 440*x^10 +...
Compare the g.f to the square of the Jacobi theta_3 series:
theta_3(x)^2 = 1 + 4*x + 4*x^2 + 4*x^4 + 8*x^5 + 4*x^8 + 4*x^9 + 8*x^10 +...+ A004018(n)*x^n +...
The g.f. equals the sum:
A(x) = 1 + 4*x/(1-x-x^2) - 4*2*x^3/(1-4*x^3-x^6) + 4*5*x^5/(1-11*x^5-x^10) - 4*13*x^7/(1-29*x^7-x^14) + 4*34*x^9/(1-76*x^9-x^18) - 4*89*x^11/(1-199*x^11-x^22) + 4*233*x^13/(1-521*x^13-x^26) - 4*610*x^15/(1-1364*x^15-x^30) +...
which involves odd-indexed Fibonacci and Lucas numbers.

Links

Crossrefs

Cf. A205508, A204060, A203847, A004018, A000204 (Lucas).

Programs

  • Mathematica
    Join[{1}, Table[Fibonacci[n]*SquaresR[2, n], {n,1,50}]] (* G. C. Greubel, Mar 05 2017 *)
  • PARI
    {A004018(n)=polcoeff((1+2*sum(k=1,sqrtint(n+1),x^(k^2),x*O(x^n)))^2,n)}
{a(n)=if(n==0,1,fibonacci(n)*A004018(n))}
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff((1+4*sum(m=0,n+1,(-1)^m*fibonacci(2*m+1)*x^(2*m+1)/(1-Lucas(2*m+1)*x^(2*m+1)-x^(4*m+2)+x*O(x^n)))),n)}

Formula

G.f.: 1 + 4*Sum_{n>=0} (-1)^n*Fibonacci(2*n+1)*x^(2*n+1) / (1 - Lucas(2*n+1)*x^(2*n+1) - x^(4*n+2)), where Lucas(n) = A000204(n).

A205964 a(n) = Fibonacci(n)*A000143(n) for n>=1 with a(0)=1, where A000143(n) is the number of ways of writing n as a sum of 8 squares.

Original entry on oeis.org

1, 16, 112, 896, 3408, 10080, 25088, 71552, 195888, 411808, 776160, 1896768, 4580352, 8194144, 14525056, 34433280, 73890768, 125562528, 219081856, 458906560, 968315040, 1686909952, 2642197824, 5579174016, 12110579712, 18907500400, 29884043168, 64236542720
Offset: 0

Views

Author

Paul D. Hanna, Feb 03 2012

Keywords

Comments

Compare g.f. to the Lambert series of A000143: 1 + 16*Sum_{n>=1} n^3*x^n/(1 - (-x)^n).

Examples

			G.f.: A(x) = 1 + 16*x + 112*x^2 + 896*x^3 + 3408*x^4 + 10080*x^5 +...
where A(x) = 1 + 1*16*x + 1*112*x^2 + 2*448*x^3 + 3*1136*x^4 + 5*2016*x^5 + 8*3136*x^6 + 13*5504*x^7 + 21*9328*x^8 +...+ Fibonacci(n)*A000143(n)*x^n +...
The g.f. is also given by the identity:
A(x) = 1 + 16*( 1*1*x/(1+x-x^2) + 1*8*x^2/(1-3*x^2+x^4) + 2*27*x^3/(1+4*x^3-x^6) + 3*64*x^4/(1-7*x^4+x^8) + 5*125*x^5/(1+11*x^5-x^10) + 8*216*x^6/(1-18*x^6+x^12) + 13*343*x^7/(1+29*x^7-x^14) +...).

Links

Crossrefs

Cf. A000143, A205507, A205963, A203847, A000204 (Lucas).
Cf. A209444 (Pell variant).

Programs

  • Mathematica
    Join[{1}, Table[Fibonacci[n]*SquaresR[8, n], {n,1,30}]] (* G. C. Greubel, Mar 05 2017 *)
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(1+16*sum(m=1,n,fibonacci(m)*m^3*x^m/(1-Lucas(m)*(-x)^m+(-1)^m*x^(2*m)+x*O(x^n))),n)}
for(n=0,31,print1(a(n),", "))

Formula

G.f.: 1 + 16*Sum_{n>=1} Fibonacci(n)*n^3*x^n/(1 - Lucas(n)*(-x)^n + (-1)^n*x^(2*n)).

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 + ...

Links

Crossrefs

Cf. A008655, A205967, A205969, A203847, A000204 (Lucas).
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)).

A205970 a(n) = Fibonacci(n)*A132973(n) for n>=1, with a(0)=1, where A132973 lists the coefficients in psi(-q)^3/psi(-q^3) and where psi() is a Ramanujan theta function.

Original entry on oeis.org

1, -3, 3, -6, 9, 0, 24, -78, 63, -102, 0, 0, 432, -1398, 2262, 0, 2961, 0, 7752, -25086, 0, -65676, 0, 0, 139104, -225075, 728358, -589254, 1906866, 0, 0, -8077614, 6534927, 0, 0, 0, 44791056, -144946902, 234529014, -379475916, 0, 0, 1607485776, -2600966622, 0
Offset: 0

Views

Author

Paul D. Hanna, Feb 04 2012

Keywords

Comments

Compare g.f. to the Lambert series of A132973:
1 - 3*Sum_{n>=0} x^(6*n+1)/(1+x^(6*n+1)) - x^(6*n+5)/(1+x^(6*n+5)).

Examples

			G.f.: A(x) = 1 - 3*x + 3*x^2 - 6*x^3 + 9*x^4 + 24*x^6 - 78*x^7 + 63*x^8 +...
where A(x) = 1 - 1*3*x + 1*3*x^2 - 2*3*x^3 + 3*3*x^4 + 8*3*x^6 - 13*6*x^7 + 21*3*x^8 +...+ Fibonacci(n)*A132973(n)*x^n +...
The g.f. is also given by the identity:
A(x) = 1 - 3*( 1*x/(1+x-x^2) - 5*x^5/(1+11*x^5-x^10) + 13*x^7/(1+29*x^7-x^14) - 89*x^11/(1+199*x^11-x^22) + 233*x^13/(1+521*x^13-x^26) - 1597*x^17/(1+3571*x^17-x^34) +...).

Links

Crossrefs

Cf. A132973, A205969, A205971, A203847.
Cf. A209450 (Pell variant).

Programs

  • Mathematica
    A132973:= CoefficientList[Series[(-1)^(-1/4)*EllipticTheta[2, 0, I*Sqrt[q]]^3/EllipticTheta[2, 0, I*Sqrt[q^3]]/4, {q, 0, 60}], q]; Table[If[n == 0, 1, Fibonacci[n]*A132973[[n + 1]]], {n, 0, 50}] (* G. C. Greubel, Dec 03 2017 *)
  • PARI
    {Lucas(n)=fibonacci(n-1)+fibonacci(n+1)}
{a(n)=polcoeff(1 - 3*sum(m=0,n, fibonacci(6*m+1)*x^(6*m+1)/(1+Lucas(6*m+1)*x^(6*m+1)-x^(12*m+2) +x*O(x^n)) - fibonacci(6*m+5)*x^(6*m+5)/(1+Lucas(6*m+5)*x^(6*m+5)-x^(12*m+10) +x*O(x^n)) ),n)}
for(n=0,61,print1(a(n),", "))

Formula

G.f.: 1 - 3*Sum_{n>=0} Fibonacci(6*n+1)*x^(6*n+1)/(1 + Lucas(6*n+1) * x^(6*n+1) - x^(12*n+2)) - Fibonacci(6*n+5)*x^(6*n +5)/(1 + Lucas(6*n+5) * x^(6*n+5) - x^(12*n+10)).
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