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A222732
Total sum of parts of multiplicity 4 in all partitions of n.
2
1, 0, 1, 1, 4, 4, 6, 8, 16, 19, 30, 36, 59, 73, 106, 135, 191, 242, 331, 420, 569, 712, 941, 1183, 1546, 1931, 2476, 3087, 3933, 4872, 6137, 7568, 9471, 11629, 14427, 17647, 21758, 26499, 32470, 39393, 48030, 58028, 70385, 84749, 102348, 122794, 147633, 176554
OFFSET
4,5
LINKS
FORMULA
G.f.: (x^4/(1-x^4)^2-x^5/(1-x^5)^2)/Product_{i>=1}(1-x^i).
a(n) ~ 9 * sqrt(3) * exp(Pi*sqrt(2*n/3)) / (800 * Pi^2). - Vaclav Kotesovec, May 29 2018
MAPLE
b:= proc(n, p) option remember; `if`(n=0, [1, 0], `if`(p<1, [0, 0],
add((l->`if`(m=4, l+[0, l[1]*p], l))(b(n-p*m, p-1)), m=0..n/p)))
end:
a:= n-> b(n, n)[2]:
seq(a(n), n=4..55);
MATHEMATICA
b[n_, p_] := b[n, p] = If[n == 0 && p == 0, {1, 0}, If[p == 0, Array[0&, n+2], Sum[Function[l, ReplacePart[l, m+2 -> p*l[[1]] + l[[m+2]]]][Join[b[n-p*m, p-1], Array[0&, p*m]]], {m, 0, n/p}]]]; a[n_] := b[n, n][[6]]; Table[a[n], {n, 4, 55}] (* Jean-François Alcover, Jan 24 2014, after Alois P. Heinz *)
CROSSREFS
Column k=4 of A222730.
Sequence in context: A175216 A053639 A100090 * A363703 A074161 A201401
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Mar 03 2013
STATUS
approved