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 1-5 of 5 results.

A300975 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k^3))^n.

Original entry on oeis.org

1, 1, 3, 10, 35, 126, 462, 1716, 6443, 24391, 92928, 355862, 1368458, 5280744, 20438148, 79302960, 308385355, 1201536286, 4689450021, 18330233110, 71747534460, 281177705490, 1103163479190, 4332522733560, 17031238725410, 67007449610751, 263841039245280, 1039628691988795
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 17 2018

Keywords

Comments

Number of partitions of n into cubes 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^3*j, i-1), j=0..n/i^3)))
          end: b(n, iroot(n, 3))
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Mar 17 2018
  • Mathematica
    Table[SeriesCoefficient[Product[1/(1 - x^k^3)^n, {k, 1, n}], {x, 0, n}], {n, 0, 27}]

Formula

a(n) ~ c * d^n / sqrt(n), where d = 4.0147940395164236614815683662796167488... and c = 0.2726202310726337579308600184572222... - Vaclav Kotesovec, Mar 23 2018

A301335 a(n) = [x^n] 1/(1 + (1/2)*n*(1 - theta_3(x))), where theta_3() is the Jacobi theta function.

Original entry on oeis.org

1, 1, 4, 27, 260, 3175, 47304, 833147, 16941120, 390611331, 10070060200, 287028156162, 8962583345856, 304255011200647, 11156593415089808, 439452231820920000, 18505340390664634384, 829599437871129843839, 39447684087807950938908, 1983038000428208822539998, 105080571577382659860160800
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 18 2018

Keywords

Comments

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

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[1/(1 + (1/2) n (1 - EllipticTheta[3, 0, x])), {x, 0, n}], {n, 0, 20}]
    Table[SeriesCoefficient[1/(1 - n Sum[x^k^2, {k, 1, n}]), {x, 0, n}], {n, 0, 20}]

Formula

a(n) = [x^n] 1/(1 - n*Sum_{k>=1} x^(k^2)).
a(n) ~ n^n * (1 + 1/n^2 - 3/n^3 + 1/(2*n^4) - 13/(2*n^5) + 127/(6*n^6) - 4/n^7 + 335/(8*n^8) - 665/(4*n^9) + 337/(15*n^10) + ...). - Vaclav Kotesovec, Mar 19 2018

A301518 a(n) = [x^n] Product_{k>=1} (1 + x^(k^2))^n.

Original entry on oeis.org

1, 1, 1, 1, 5, 26, 91, 246, 589, 1468, 4226, 13311, 41471, 122864, 351184, 1001876, 2920957, 8698612, 26070130, 77707056, 229959130, 679050870, 2011457295, 5986185690, 17866178695, 53343031301, 159149943668, 474683353849, 1416730630936, 4233405443596
Offset: 0

Views

Author

Vaclav Kotesovec, Mar 23 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[(1 + x^(k^2))^n, {k, 1, n}], {x, 0, n}], {n, 0, 30}]

Formula

a(n) ~ c * d^n / sqrt(n), where d = 3.04074590736461391963643911... and c = 0.2268848664201836146769277...

A301458 a(n) = [x^n] Product_{k>=1} 1/(1 - x^(k*(k+1)/2))^n.

Original entry on oeis.org

1, 1, 3, 13, 51, 201, 825, 3431, 14355, 60493, 256463, 1092268, 4669665, 20029036, 86148373, 371434173, 1604845715, 6946936628, 30121158813, 130795358333, 568709929191, 2475778867547, 10789659781640, 47069225185789, 205524447217185, 898163031782576, 3928112419640126
Offset: 0

Views

Author

Ilya Gutkovskiy, Mar 21 2018

Keywords

Comments

Number of partitions of n into triangular numbers of n kinds.

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[1/(1 - x^(k (k + 1)/2))^n, {k, 1, n}], {x, 0, n}], {n, 0, 26}]

A302836 a(n) = [x^n] Product_{k>=1} 1/(1 - n*x^(k^2)).

Original entry on oeis.org

1, 1, 4, 27, 260, 3150, 46872, 825944, 16810048, 387952668, 10010010100, 285526191874, 8921263237056, 303013028232642, 11116057874586840, 438023675344410000, 18451248777413066768, 827408674110381669305, 39353155876513869320412, 1978708139249503877752798
Offset: 0

Views

Author

Ilya Gutkovskiy, Apr 13 2018

Keywords

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[Product[1/(1 - n x^k^2), {k, 1, n}], {x, 0, n}], {n, 0, 19}]

Formula

a(n) ~ n^n * (1 + 1/n^3 + 1/n^6 + 1/n^8 + 1/n^9 + 1/n^11 + 1/n^12 + 1/n^14 + 2/n^15 + 1/n^16 + 1/n^17 + 2/n^18 + 1/n^19 + 1/n^20 + 2/n^21 + 1/n^22 + 2/n^23 + 4/n^24 + 1/n^25 + 2/n^26 + 4/n^27 + 1/n^28 + 2/n^29 + 5/n^30 + ...), for coefficients see A111178. - Vaclav Kotesovec, Apr 13 2018
Showing 1-5 of 5 results.