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A341459 Number of compositions of n^2 into n prime parts. 3
1, 0, 1, 4, 22, 241, 2696, 35218, 529888, 8998419, 169486964, 3496417024, 78344008779, 1891733424205, 48923563968087, 1347813311456319, 39371345548420060, 1214570579814316742, 39430967625404799740, 1343040950675651131103, 47862610677098010505554 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
FORMULA
a(n) = A121303(n^2,n).
EXAMPLE
a(3) = 4: 333, 225, 252, 522.
MAPLE
b:= proc(n, t) option remember;
`if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add(
`if`(isprime(j), b(n-j, t-1), 0), j=1..n)))
end:
a:= n-> b(n^2, n):
seq(a(n), n=0..22);
MATHEMATICA
b[n_, t_] := b[n, t] =
If[n == 0, If[t == 0, 1, 0], If[t < 1, 0, Sum[
If[PrimeQ[j], b[n-j, t-1], 0], {j, 1, n}]]];
a[n_] := b[n^2, n];
Table[a[n], {n, 0, 22}] (* Jean-François Alcover, May 02 2022, after Alois P. Heinz *)
CROSSREFS
Sequence in context: A137158 A025135 A125801 * A195227 A265908 A359111
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 12 2021
STATUS
approved

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Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)