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.

A319308 Expansion of theta_4(q)^20 in powers of q = exp(Pi i t).

Original entry on oeis.org

1, -40, 760, -9120, 77560, -497648, 2508000, -10232640, 34729720, -100906760, 259114704, -606957280, 1327461600, -2738111280, 5341699520, -9915552192, 17701924600, -30615844560, 51294999960, -83279292960, 131880275664, -204949382400, 312126610080, -464844224960, 680432137440
Offset: 0

Views

Author

Seiichi Manyama, Sep 16 2018

Keywords

Crossrefs

theta_4(q)^b: A002448 (b=1), A104794 (b=2), A213384 (b=3), A096727 (b=4), A035016 (b=8), A286346 (b=12), A319307 (b=16), this sequence (b=20), A319309 (b=24), A319310 (b=28).

Formula

Expansion of eta(q)^40 / eta(q^2)^20 in powers of q.

A319309 Expansion of theta_4(q)^24 in powers of q = exp(Pi i t).

Original entry on oeis.org

1, -48, 1104, -16192, 170064, -1362336, 8662720, -44981376, 195082320, -721175536, 2319457632, -6631997376, 17231109824, -41469483552, 93703589760, -200343312768, 407488018512, -793229226336, 1487286966928, -2697825744960, 4744779429216, -8110465650176
Offset: 0

Views

Author

Seiichi Manyama, Sep 16 2018

Keywords

Crossrefs

theta_4(q)^b: A002448 (b=1), A104794 (b=2), A213384 (b=3), A096727 (b=4), A035016 (b=8), A286346 (b=12), A319307 (b=16), A319308 (b=20), this sequence (b=24), A319310 (b=28).
Cf. A000156.

Formula

Expansion of eta(q)^48 / eta(q^2)^24 in powers of q.

A319310 Expansion of theta_4(q)^28 in powers of q = exp(Pi i t).

Original entry on oeis.org

1, -56, 1512, -26208, 327656, -3147984, 24189984, -152867520, 811401192, -3681079640, 14500933104, -50376047904, 156797510688, -444306558864, 1163495873088, -2851049839680, 6597606440936, -14512424533488, 30505974273096, -61591664700384, 119983597365744, -226303038736128
Offset: 0

Views

Author

Seiichi Manyama, Sep 16 2018

Keywords

Crossrefs

theta_4(q)^b: A002448 (b=1), A104794 (b=2), A213384 (b=3), A096727 (b=4), A035016 (b=8), A286346 (b=12), A319307 (b=16), A319308 (b=20), A319309 (b=24), this sequence (b=28).

Formula

Expansion of eta(q)^56 / eta(q^2)^28 in powers of q.

A008409 Theta series of 16-dimensional Barnes-Wall lattice.

Original entry on oeis.org

1, 0, 4320, 61440, 522720, 2211840, 8960640, 23224320, 67154400, 135168000, 319809600, 550195200, 1147643520, 1771683840, 3371915520, 4826603520, 8593797600, 11585617920, 19590534240, 25239859200, 40979580480, 50877235200
Offset: 0

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Author

Keywords

Examples

			1 + 4320*q^4 + 61440*q^6 + 522720*q^8 + 2211840*q^10 + 8960640*q^12 + ...
		

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 130, p. 131 Equation (132).

Crossrefs

A008774(2*n) = a(n).

Programs

  • Mathematica
    f[q_] := 1/2*(EllipticTheta[2, 0, q]^16 + EllipticTheta[3, 0, q]^16 + EllipticTheta[4, 0, q]^16 + 30*EllipticTheta[2, 0, q]^8*EllipticTheta[3, 0, q]^8); Series[f[q], {q, 0, 21}] // CoefficientList[#, q]& (* Jean-François Alcover, May 15 2013 *)
  • PARI
    {a(n) = local(A1, A2) ; if( n<0, 0, A1 = eta(x + x * O(x^n))^8; A2 = eta(x^2 + x * O(x^n))^8; polcoeff( (A1^6 + 32 * x * A1^3 * A2^3 + 4096 * x^2 * A2^6) / ( A1 * A2 )^2, n))} /* Michael Somos, Nov 29 2007 */

Formula

Expansion of ( theta_2(q)^16 + theta_3(q)^16 + theta_4(q)^16 + 30 * theta_2(q)^8 * theta_3(q)^8 ) / 2 in powers of q. - [Conway and Sloane]
Expansion of E_4(q^2)^2 + (E_4(q) - E_4(q^2))^2 / 15 in powers of q. - Michael Somos, Nov 29 2007
Expansion of ( eta(q)^48 + 32 * eta(q)^24 * eta(q^2)^24 + 4096 * eta(q^2)^48 ) / ( eta(q) * eta(q^2) )^16 in powers of q. - Michael Somos, Nov 29 2007
G.f. is Fourier series of a weight 8 level 2 modular form. f(-1 / (2 t)) = 16 (t/i)^8 f(t) where q = exp(2 Pi i t). - Michael Somos, Nov 29 2007
Showing 1-4 of 4 results.