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.

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A092322 Sum of largest parts of all partitions of n into odd parts.

Original entry on oeis.org

1, 1, 4, 4, 9, 12, 19, 24, 36, 48, 64, 83, 108, 140, 179, 224, 280, 352, 432, 532, 652, 795, 960, 1160, 1392, 1669, 1992, 2368, 2804, 3320, 3908, 4592, 5388, 6300, 7349, 8560, 9940, 11524, 13340, 15401, 17752, 20436, 23472, 26920, 30840, 35256, 40252, 45900
Offset: 1

Views

Author

Vladeta Jovovic, Feb 15 2004

Keywords

Comments

a(n) = Sum_{k>=1} k*A116799(n,k). - Emeric Deutsch, Feb 24 2006

Examples

			a(5)=9 because the partitions of 5 into odd parts are [5],[3,1,1] and [1,1,1,1,1] and the largest parts add up to 5+3+1=9.
		

Crossrefs

Programs

  • Maple
    g:=sum((2*n-1)*x^(2*n-1)/Product(1-x^(2*k-1),k=1..n),n=1..30): gser:=series(g,x=0,50): seq(coeff(gser,x^n),n=1..48); # 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, 1, n}], {n, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Jul 06 2019 *)

Formula

G.f.: Sum_{n>=1} (2*n-1)*x^(2*n-1)/Product_{k=1..n} (1-x^(2*k-1)).

Extensions

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

A116856 Triangle read by rows: T(n,k) is the number of partitions of n into odd parts such that the smallest part is k (n>=1, k>=1).

Original entry on oeis.org

1, 1, 1, 0, 1, 2, 2, 0, 0, 0, 1, 3, 0, 1, 4, 0, 0, 0, 0, 0, 1, 5, 0, 1, 6, 0, 1, 0, 0, 0, 0, 0, 1, 8, 0, 1, 0, 1, 10, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 12, 0, 2, 0, 1, 15, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 18, 0, 2, 0, 1, 0, 1, 22, 0, 3, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 27, 0, 3, 0, 1, 0, 1, 32, 0, 4, 0, 1, 0
Offset: 1

Views

Author

Emeric Deutsch, Feb 24 2006

Keywords

Comments

Row 2n-1 has 2n-1 terms; row 4n+2 has 2n+1 terms; row 4n has 2n-1 terms. Row sums yield A000009.

Examples

			T(12,3)=2 because we have [9,3] and [3,3,3,3].
Triangle starts:
1;
1;
1,0,1;
2;
2,0,0,0,1;
3,0,1;
4,0,0,0,0,0,1
		

Crossrefs

Programs

  • Maple
    g:=sum(t^(2*j-1)*x^(2*j-1)/product(1-x^(2*i-1),i=j..20),j=1..30): gser:=simplify(series(g,x=0,20)): for n from 1 to 17 do P[n]:=sort(coeff(gser,x^n)) od: d:=proc(n) if n mod 2 = 1 then n elif n mod 4 = 2 then n/2 else n/2-1 fi end: for n from 1 to 17 do seq(coeff(P[n],t^j),j=1..d(n)) od; # yields sequence in triangular form; d(n) is the degree of the polynomial P[n]
  • Mathematica
    imax = 18;
    Rest@CoefficientList[#, t]& /@ Rest@CoefficientList[Sum[t^(2j-1)*x^(2j-1)/ Product[1 - x^(2i-1), {i, j, imax}], {j, 1, imax}] + O[x]^imax, x] // Flatten (* Jean-François Alcover, Aug 26 2024 *)

Formula

G.f.: Sum_{j=1..oo} t^(2*j-1)*x^(2*j-1)/Product_{i=j..oo} 1-x^(2*i-1).
T(n,2k)=0.
Sum_{k>=1} k*T(n,k) = A092314(n).
Showing 1-2 of 2 results.