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.

A035690 Number of partitions of n into parts 8k+3 and 8k+4 with at least one part of each type.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 3, 1, 1, 3, 4, 1, 3, 4, 7, 3, 4, 8, 10, 4, 8, 11, 15, 8, 11, 18, 21, 11, 19, 24, 30, 19, 25, 37, 42, 25, 40, 50, 56, 41, 53, 70, 79, 54, 77, 95, 103, 80, 103, 129, 141, 106, 144, 172, 183, 151, 189, 228, 246, 197, 257, 301, 314
Offset: 1

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Author

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Crossrefs

Programs

  • Mathematica
    nmax = 71; s1 = Range[0, nmax/8]*8 + 3; 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 = 71; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(8 k + 3)), {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 + 3)))*(-1 + 1/Product_{k>=0} (1 - x^(8 k + 4))). - Robert Price, Aug 15 2020

A035692 Number of partitions of n into parts 8k+3 and 8k+6 with at least one part of each type.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 2, 2, 0, 2, 3, 0, 4, 3, 3, 4, 4, 4, 6, 4, 8, 6, 9, 9, 8, 11, 13, 8, 19, 14, 15, 21, 18, 19, 30, 19, 32, 32, 29, 38, 41, 36, 53, 43, 56, 59, 59, 67, 75, 70, 93, 81, 102, 105, 105, 122, 133, 123, 165, 145, 170, 189, 183, 203, 237
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 75; s1 = Range[0, nmax/8]*8 + 3; s2 = Range[0, nmax/8]*8 + 6;
    Table[Count[IntegerPartitions[n, All, s1~Join~s2],
    x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* Robert Price, Aug 15 2020 *)
    nmax = 75; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(8 k + 3)), {k, 0, nmax}])*(-1 + 1/Product[(1 - x^(8 k + 6)), {k, 0, nmax}]), {x, 0, nmax}], x]  (* Robert Price, Aug 15 2020*)

Formula

G.f.: (-1 + 1/Product_{k>=0} (1 - x^(8 k + 3)))*(-1 + 1/Product_{k>=0} (1 - x^(8 k + 6))). - Robert Price, Aug 15 2020

A035460 Number of partitions of n into parts 8k+3 or 8k+5.

Original entry on oeis.org

1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 2, 1, 2, 2, 2, 3, 2, 3, 4, 3, 5, 5, 4, 7, 6, 7, 9, 7, 10, 11, 10, 14, 13, 14, 18, 16, 20, 22, 21, 27, 26, 29, 34, 32, 39, 41, 41, 51, 49, 54, 63, 60, 71, 76, 76, 90, 91, 98, 111, 110, 125, 133, 137, 157, 159, 172, 191, 192, 216, 229, 235, 266, 272
Offset: 0

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Author

Keywords

Examples

			G.f. = 1 + x^3 + x^5 + x^6 + x^8 + x^9 + x^10 + 2*x^11 + x^12 + 2*x^13 + ...
		

Crossrefs

Cf. A035691.

Programs

  • Mathematica
    a[ n_] := SeriesCoefficient[ 1 / QPochhammer[ x^3, x^8] / QPochhammer[ x^5, x^8], {x, 0, n}]; (* Michael Somos, Jun 03 2014 *)
    nmax = 100; CoefficientList[Series[Product[1/((1 - x^(8k+3))*(1 - x^(8k+5))), {k, 0, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Aug 26 2015 *)
    nmax = 60; kmax = nmax/8;
    s = Flatten[{Range[0, kmax]*8 + 3}~Join~{Range[0, kmax]*8 + 5}];
    Table[Count[IntegerPartitions@n, x_ /; SubsetQ[s, x]], {n, 0, nmax}] (* Robert Price, Aug 04 2020 *)
  • PARI
    a(n)=if(n<0,0,polcoeff(1/prod(k=1, n, 1-(k%8==3||k%8==5)*x^k, 1+x*O(x^n)), n))

Formula

Expansion of f(-x^8) / f(-x^3, -x^5) in powers of x where f() is a Ramanujan theta function. - Michael Somos, Jun 03 2014
Euler transform of period 8 sequence [ 0, 0, 1, 0, 1, 0, 0, 0, ...]. - Michael Somos, Jun 03 2014
a(n) ~ (3-2*sqrt(2))^(1/4) * exp(Pi*sqrt(n/6)) / (4 * 3^(1/4) * n^(3/4)). - Vaclav Kotesovec, Aug 26 2015
Showing 1-3 of 3 results.