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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A004534 Theta series of {D_14}^{+} lattice.

Original entry on oeis.org

1, 0, 0, 0, 364, 0, 0, 8192, 16044, 0, 0, 114688, 200928, 0, 0, 745472, 1089452, 0, 0, 3096576, 4196920, 0, 0, 9691136, 12547808, 0, 0, 25346048, 31553344, 0, 0, 58261504, 70439852, 0, 0, 120553472, 142487436
Offset: 0

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Author

Keywords

References

  • J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 120.

Crossrefs

Cf. A000122 (theta_3(q)), A002448 (theta_4(q)), A022045.

Formula

From Seiichi Manyama, Oct 21 2018: (Start)
Expansion of (theta_2(q)^14 + theta_3(q)^14 + theta_4(q)^14)/2 in powers of q^(1/2).
Expansion of (Sum_{k=-inf..inf} q^((k+1/2)^2))^14 + (Sum_{k=-inf..inf} q^(k^2))^14 + (Sum_{k=-inf..inf} (-1)^k * q^(k^2))^14 in powers of q^(1/2). (End)

A297331 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of (theta_3(q^(1/2))^k + theta_4(q^(1/2))^k)/2.

Original entry on oeis.org

1, 1, 0, 1, 0, 0, 1, 4, 2, 0, 1, 12, 4, 0, 0, 1, 24, 6, 0, 0, 0, 1, 40, 24, 24, 4, 0, 0, 1, 60, 90, 96, 12, 8, 0, 0, 1, 84, 252, 240, 24, 24, 0, 0, 0, 1, 112, 574, 544, 200, 144, 8, 0, 2, 0, 1, 144, 1136, 1288, 1020, 560, 96, 48, 4, 0, 0, 1, 180, 2034, 3136, 3444, 1560, 400, 192, 6, 4, 0, 0
Offset: 0

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Author

Ilya Gutkovskiy, Dec 28 2017

Keywords

Examples

			Square array begins:
1,  1,  1,   1,    1,    1,  ...
0,  0,  4,  12,   24,   40,  ...
0,  2,  4,   6,   24,   90,  ...
0,  0,  0,  24,   96,  240,  ...
0,  0,  4,  12,   24,  200,  ...
0,  0,  8,  24,  144,  560,  ...
		

Crossrefs

Programs

  • Mathematica
    Table[Function[k, SeriesCoefficient[(EllipticTheta[3, 0, q^(1/2)]^k + EllipticTheta[4, 0, q^(1/2)]^k)/2, {q, 0, n}]][j - n], {j, 0, 11}, {n, 0, j}] // Flatten

Formula

G.f. of column k: (theta_3(q^(1/2))^k + theta_4(q^(1/2))^k)/2, where theta_() is the Jacobi theta function.
Showing 1-2 of 2 results.