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.

A035684 Number of partitions of n into parts 8k+1 and 8k+7 with at least one part of each type.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 4, 4, 4, 4, 4, 4, 5, 7, 10, 11, 11, 11, 11, 12, 14, 18, 23, 25, 26, 26, 27, 29, 33, 40, 47, 52, 54, 56, 58, 62, 70, 81, 93, 101, 107, 111, 116, 124, 137, 155, 172, 188, 199, 208, 218, 233, 255, 282, 311, 336, 357, 374, 393
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 68; s1 = Range[0, nmax/8]*8 + 1; s2 = Range[0, nmax/8]*8 + 7;
    Table[Count[IntegerPartitions[n, All, s1~Join~s2], x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* Robert Price, Aug 15 2020 *)
    nmax = 68; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(8 k + 1)), {k, 0, nmax}])*(-1 + 1/Product[(1 - x^(8 k + 7)), {k, 0, nmax}]), {x, 0, nmax}], x]  (* Robert Price, Aug 15 2020*)

Formula

G.f.: (-1 + 1/Product_{k>=0} (1 - x^(8*k + 1)))*(-1 + 1/Product_{k>=0} (1 - x^(8*k + 7))). - Robert Price, Aug 15 2020

A035686 Number of partitions of n into parts 8k+2 and 8k+4 with at least one part of each type.

Original entry on oeis.org

0, 0, 0, 0, 0, 1, 0, 1, 0, 2, 0, 2, 0, 5, 0, 5, 0, 8, 0, 8, 0, 14, 0, 15, 0, 22, 0, 23, 0, 34, 0, 37, 0, 51, 0, 54, 0, 74, 0, 81, 0, 107, 0, 116, 0, 150, 0, 165, 0, 210, 0, 229, 0, 287, 0, 316, 0, 392, 0, 430, 0, 526, 0, 580, 0, 704, 0, 774, 0, 929, 0, 1024, 0, 1223, 0, 1347, 0
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 77; s1 = Range[0, nmax/8]*8 + 2; 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 15 2020 *)
    nmax = 77; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(8 k + 2)), {k, 0, nmax}])*(-1 + 1/Product[(1 - x^(8 k + 4)), {k, 0, nmax}]), {x, 0, nmax}], x]  (* Robert Price, Aug 15 2020*)

Formula

G.f.: (-1 + 1/Product_{k>=0} (1 - x^(8 k + 2)))*(-1 + 1/Product_{k>=0} (1 - x^(8 k + 4))). - Robert Price, Aug 15 2020

A035454 Number of partitions of n into parts 8k+2 or 8k+3.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 8, 8, 10, 11, 13, 13, 16, 16, 19, 20, 23, 25, 29, 30, 35, 37, 41, 44, 50, 53, 60, 64, 72, 76, 85, 90, 100, 107, 118, 126, 140, 148, 163, 174, 190, 203, 223, 237, 260, 277, 301, 321, 349, 371, 403, 430, 466, 496, 537
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A035685.

Programs

  • Maple
    nmax:= 100:
    g:= mul(1/(1-x^(8*k+2))/(1-x^(8*k+3)),k=0..(nmax-2)/8):
    S:= series(g,x,nmax+1):
    seq(coeff(S,x,j),j=1..nmax); # Robert Israel, Dec 11 2018
  • Mathematica
    nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(8k+2))*(1 - x^(8k+3))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 26 2015 *)
    nmax = 60; kmax = nmax/8;
    s = Flatten[{Range[0, kmax]*8 + 2}~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(1/4) * Gamma(3/8) / (8 * 2^(5/16) * 3^(1/16) * Pi^(11/8) * n^(9/16)). - Vaclav Kotesovec, Aug 26 2015
G.f.: Product_{k>=0} 1/((1-x^(8*k+2))*(1-x^(8*k+3))). - Robert Israel, Dec 11 2018
Showing 1-3 of 3 results.