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 1-3 of 3 results.

A035673 Number of partitions of n into parts 8k and 8k+2 with at least one part of each type.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 4, 0, 4, 0, 4, 0, 4, 0, 10, 0, 11, 0, 11, 0, 11, 0, 22, 0, 25, 0, 26, 0, 26, 0, 44, 0, 51, 0, 54, 0, 55, 0, 84, 0, 98, 0, 105, 0, 108, 0, 153, 0, 178, 0, 193, 0, 200, 0, 269, 0, 313, 0, 341, 0, 356, 0, 459, 0, 531, 0, 582, 0, 611, 0
Offset: 1

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Author

Keywords

Crossrefs

Bisections give: A035621 (even part), A000004 (odd part).

Programs

  • Mathematica
    nmax = 81; s1 = Range[1, nmax/8]*8; s2 = Range[0, nmax/8]*8 + 2;
    Table[Count[IntegerPartitions[n, All, s1~Join~s2],
    x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* Robert Price, Aug 12 2020 *)
    nmax = 81; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(8 k)), {k, 1, nmax}])*(-1 + 1/Product[(1 - x^(8 k + 2)), {k, 0, nmax}]), {x, 0, nmax}], x]  (* Robert Price, Aug 12 2020 *)

Formula

G.f.: (-1 + 1/Product_{k>=0} (1 - x^(8*k + 2)))*(-1 + 1/Product_{k>=1} (1 - x^(8*k))). - Robert Price, Aug 12 2020

A035675 Number of partitions of n into parts 8k and 8k+4 with at least one part of each type.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 4, 0, 0, 0, 4, 0, 0, 0, 10, 0, 0, 0, 11, 0, 0, 0, 22, 0, 0, 0, 25, 0, 0, 0, 44, 0, 0, 0, 51, 0, 0, 0, 83, 0, 0, 0, 98, 0, 0, 0, 149, 0, 0, 0, 177, 0, 0, 0, 259, 0, 0, 0, 309, 0, 0, 0, 436, 0, 0, 0, 521, 0, 0, 0, 716, 0, 0, 0, 857, 0, 0
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 90; s1 = Range[1, nmax/8]*8; s2 = Range[0, nmax/8]*8 + 4;
    Table[Count[IntegerPartitions[n, All, s1~Join~s2],
    x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* Robert Price, Aug 13 2020 *)
    nmax = 90; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(8 k)), {k, 1, nmax}])*(-1 + 1/Product[(1 - x^(8 k + 4)), {k, 0, nmax}]), {x, 0, nmax}], x]  (* Robert Price, Aug 13 2020 *)

Formula

G.f.: (-1 + 1/Product_{k>=0} (1 - x^(8*k + 4)))*(-1 + 1/Product_{k>=1} (1 - x^(8*k))). - Robert Price, Aug 13 2020

A035443 Number of partitions of n into parts 8k or 8k+3.

Original entry on oeis.org

0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 2, 1, 0, 2, 1, 2, 2, 1, 4, 2, 1, 5, 2, 4, 5, 2, 8, 5, 2, 10, 5, 7, 11, 5, 14, 11, 5, 19, 11, 12, 21, 11, 24, 22, 11, 33, 22, 22, 38, 22, 41, 40, 22, 58, 41, 37, 68, 41, 67, 73, 41, 95, 75, 63, 114, 76, 108, 124, 76, 155, 129, 106, 188, 131, 173
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A035674.

Programs

  • Mathematica
    nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(8k+8))*(1 - x^(8k+3))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 26 2015 *)
    nmax = 50; kmax = nmax/8;
    s = Flatten[{Range[0, kmax]*8}~Join~{Range[0, kmax]*8 + 3}];
    Table[Count[IntegerPartitions@n, x_ /; SubsetQ[s, x]], {n, 1, nmax}] (* Robert Price, Aug 03 2020 *)

Formula

a(n) ~ exp(Pi*sqrt(n/6)) * Gamma(3/8) / (4 * 2^(3/16) * 3^(7/16) * Pi^(5/8) * n^(15/16)). - Vaclav Kotesovec, Aug 26 2015
Showing 1-3 of 3 results.