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A229329
Total sum of 7th powers of parts in all partitions of n.
2
0, 1, 130, 2319, 18962, 99407, 400620, 1323441, 3835406, 9924912, 23736846, 52729348, 111173790, 222415631, 428578374, 794363760, 1430855958, 2500747293, 4274146464, 7130355736, 11681752260, 18764913468, 29690460150, 46211761397, 71016916110, 107622522692
OFFSET
0,3
COMMENTS
The bivariate g.f. for the partition statistic "sum of 7th powers of the parts" is G(t,x) = 1/Product_{k>=1}(1 - t^{k^7}*x^k). The g.f. g at the Formula section has been obtained by evaluating dG/dt at t=1. - Emeric Deutsch, Dec 06 2015
FORMULA
a(n) = Sum_{k=1..n} A066633(n,k) * k^7.
G.f.: g(x) = (Sum_{k>=1} k^7*x^k/(1-x^k))/Product_{q>=1}(1-x^q). - Emeric Deutsch, Dec 06 2015
a(n) ~ 288*sqrt(3)/5 * exp(Pi*sqrt(2*n/3)) * n^3. - Vaclav Kotesovec, May 28 2018
MAPLE
b:= proc(n, i) option remember; `if`(n=0, [1, 0],
`if`(i<1, [0, 0], `if`(i>n, b(n, i-1),
((g, h)-> g+h+[0, h[1]*i^7])(b(n, i-1), b(n-i, i)))))
end:
a:= n-> b(n, n)[2]:
seq(a(n), n=0..40);
# second Maple program:
g := (sum(k^7*x^k/(1-x^k), k = 1..100))/(product(1-x^k, k = 1..100)): gser := series(g, x = 0, 45): seq(coeff(gser, x, m), m = 1 .. 40); # Emeric Deutsch, Dec 06 2015
MATHEMATICA
(* T = A066633 *) T[n_, n_] = 1; T[n_, k_] /; k < n := T[n, k] = T[n - k, k] + PartitionsP[n - k]; T[_, _] = 0; a[n_] := Sum[T[n, k]*k^7, {k, 1, n}]; Array[a, 40, 0] (* Jean-François Alcover, Dec 15 2016 *)
CROSSREFS
Column k=7 of A213191.
Sequence in context: A254924 A185584 A301545 * A262108 A250212 A239094
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 20 2013
STATUS
approved