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 1-2 of 2 results.

A092314 Sum of smallest parts of all partitions of n into odd parts.

Original entry on oeis.org

1, 1, 4, 2, 7, 6, 11, 8, 18, 16, 24, 23, 34, 36, 51, 48, 66, 74, 90, 98, 126, 137, 164, 182, 220, 247, 294, 324, 380, 434, 496, 556, 650, 728, 835, 938, 1068, 1204, 1372, 1531, 1736, 1956, 2198, 2462, 2784, 3104, 3482, 3890, 4358, 4864, 5441, 6048, 6748, 7516
Offset: 1

Views

Author

Vladeta Jovovic, Feb 15 2004

Keywords

Comments

a(n) = Sum_{k>=1} k*A116856(n,k). - Emeric Deutsch, Feb 24 2006

Examples

			a(5)=7 because the partitions of 5 into odd parts are [5],[3,1,1] and [1,1,1,1,1] and the smallest parts add up to 5+1+1=7.
		

Crossrefs

Programs

  • Maple
    g:=sum((2*n-1)*x^(2*n-1)/Product(1-x^(2*k-1),k=n..30),n=1..30): gser:=series(g,x=0,57): seq(coeff(gser,x^n),n=1..54); # Emeric Deutsch, Feb 24 2006
  • Mathematica
    nmax = 50; Rest[CoefficientList[Series[Sum[(2*n - 1)*x^(2*n - 1) / Product[(1 - x^(2*k - 1)), {k, n, nmax}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)

Formula

G.f.: Sum((2*n-1)*x^(2*n-1)/Product(1-x^(2*k-1), k = n .. infinity), n = 1 .. infinity).
a(n) ~ exp(Pi*sqrt(n/3)) / (4 * 3^(1/4) * n^(3/4)). - Vaclav Kotesovec, Jul 07 2019

Extensions

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 25 2004

A116799 Triangle read by rows: T(n,k) is the number of partitions of n into odd parts such that the largest part is k (n>=1, k>=1).

Original entry on oeis.org

1, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 2, 0, 1, 1, 0, 2, 0, 1, 0, 1, 1, 0, 2, 0, 2, 0, 1, 1, 0, 3, 0, 2, 0, 1, 0, 1, 1, 0, 3, 0, 3, 0, 2, 0, 1, 1, 0, 3, 0, 4, 0, 2, 0, 1, 0, 1, 1, 0, 4, 0, 4, 0, 3, 0, 2, 0, 1, 1, 0, 4, 0, 5, 0, 4, 0, 2, 0, 1, 0, 1, 1, 0, 4, 0, 6, 0, 5, 0, 3, 0, 2, 0, 1, 1, 0, 5, 0, 7, 0, 6
Offset: 1

Views

Author

Emeric Deutsch, Feb 24 2006

Keywords

Comments

Both rows 2n-1 and 2n have 2n-1 terms. Row sums yield A000009. T(n,2k)=0. T(n,3)=A002264(n). Sum(k*T(n,k),k>=1)=A092322(n).

Examples

			T(10,5)=3 because we have [3,3,3,1], [3,3,1,1,1,1] and [3,1,1,1,1,1,1,1].
Triangle starts:
1;
1;
1,0,1;
1,0,1;
1,0,1,0,1;
1,0,2,0,1;
		

Crossrefs

Programs

  • Maple
    g:=sum(t^(2*j-1)*x^(2*j-1)/product(1-x^(2*i-1),i=1..j),j=1..40): gser:=simplify(series(g,x=0,22)): for n from 1 to 16 do P[n]:=sort(coeff(gser,x^n)) od: for n from 1 to 16 do seq(coeff(P[n],t^j),j=1..2*ceil(n/2)-1) od; # yields sequence in triangular form

Formula

G.f.=sum(t^(2j-1)*x^(2j-1)/product(1-x^(2i-1), i=1..j), j=1..infinity).
Showing 1-2 of 2 results.