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.

A300974 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k^2))^n.

Original entry on oeis.org

1, 1, 3, 10, 39, 151, 588, 2304, 9111, 36307, 145553, 586246, 2370264, 9614242, 39105580, 159444160, 651468967, 2666771488, 10934393619, 44899828056, 184616878289, 760010818689, 3132147583744, 12921037206764, 53351800567200, 220478125956426, 911839751015196, 3773836780169050
Offset: 0

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Author

Ilya Gutkovskiy, Mar 17 2018

Keywords

Comments

Number of partitions of n into squares of n kinds.

Crossrefs

Programs

  • Maple
    a:= proc(m) option remember; local b; b:= proc(n, i)
          option remember; `if`(n=0, 1, `if`(i<1, 0, add(
          binomial(m+j-1, j)*b(n-i^2*j, i-1), j=0..n/i^2)))
          end: b(n, isqrt(n))
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Mar 17 2018
  • Mathematica
    Table[SeriesCoefficient[Product[1/(1 - x^k^2)^n, {k, 1, n}], {x, 0, n}], {n, 0, 27}]

Formula

From Vaclav Kotesovec, Mar 23 2018: (Start)
a(n) ~ c * d^n / sqrt(n), where
d = 4.216358447600641565890184638418336163396695730036... and
c = 0.26442245016754864773722176155288663999776... (End)

A301742 a(n) = [x^n] 1/(1 - n*Sum_{k>=1} x^(k^3)).

Original entry on oeis.org

1, 1, 4, 27, 256, 3125, 46656, 823543, 16777224, 387420651, 10000003000, 285311729175, 8916101692416, 302875135553107, 11112007563452544, 437893910883984375, 18446744692184842496, 827240282046275783406, 39346408782249049076832, 1978419682220092642678901, 104857601064960000960000000
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 26 2018

Keywords

Comments

Number of compositions (ordered partitions) of n into cubes of n kinds.

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[1/(1 - n Sum[x^k^3, {k, 1, n}]), {x, 0, n}], {n, 0, 20}]

A303168 Expansion of Product_{k>=1} 1/(1 - x^(k^3))^k.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 3, 3, 3, 3, 3, 3, 3, 3, 6, 6, 6, 6, 6, 6, 6, 6, 10, 10, 10, 13, 13, 13, 13, 13, 18, 18, 18, 24, 24, 24, 24, 24, 30, 30, 30, 39, 39, 39, 39, 39, 46, 46, 46, 58, 58, 58, 64, 64, 72, 72, 72, 87, 87, 87, 99, 99, 112, 112, 112, 130, 130, 130, 148, 148, 166, 166, 166, 187
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 19 2018

Keywords

Comments

Number of partitions of n into 1 kind of part 1, 2 kinds of part 8, 3 kinds of part 27, ..., k kinds of part k^3.

Crossrefs

Programs

  • Mathematica
    nmax = 75; CoefficientList[Series[Product[1/(1 - x^k^3)^k, {k, 1, nmax}], {x, 0, nmax}], x]

Formula

G.f.: Product_{k>=1} 1/(1 - x^A000578(k))^k.
Showing 1-3 of 3 results.