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A327550
Number of compositions of partitions of 2n with exactly n compositions.
6
1, 2, 8, 24, 80, 224, 704, 1920, 5632, 15360, 43008, 114688, 315392, 827392, 2211840, 5767168, 15138816, 38928384, 100925440, 256901120, 657457152, 1660944384, 4202692608, 10527703040, 26424115200, 65699577856, 163477192704, 403995361280, 998043025408
OFFSET
0,2
LINKS
FORMULA
a(n) = A327549(2n,n).
a(n) ~ 2^n * exp(Pi*sqrt(2*n/3)) / (4*sqrt(3)*n). - Vaclav Kotesovec, Sep 19 2019
a(n) = A000041(n) * A000079(n). - Alois P. Heinz, Oct 08 2020
G.f.: Product_{k>=1} 1 / (1 - 2^k*x^k). - Ilya Gutkovskiy, Apr 24 2021
MAPLE
b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1 or
k<1, 0, b(n, i-1, k)+ 2^(i-1)*b(n-i, min(n-i, i), k-1)))
end:
a:= n-> b(2*n$2, n)-`if`(n=0, 0, b(2*n$2, n-1)):
seq(a(n), n=0..40);
MATHEMATICA
Table[2^n * PartitionsP[n], {n, 0, 30}] (* Vaclav Kotesovec, Oct 02 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 16 2019
STATUS
approved

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Last modified September 21 07:29 EDT 2024. Contains 376079 sequences. (Running on oeis4.)