A341122 Number of partitions of n into 4 prime powers (including 1).

1, 1, 2, 3, 5, 5, 8, 9, 12, 13, 17, 17, 22, 22, 26, 27, 33, 31, 39, 38, 44, 43, 51, 47, 58, 54, 63, 60, 71, 64, 79, 74, 88, 82, 99, 88, 108, 97, 116, 105, 126, 110, 134, 119, 141, 126, 153, 133, 164, 143, 172, 149, 184, 155, 194, 168, 204, 173, 215, 180, 227, 192, 238

Offset

4,3

Links

Table of n, a(n) for n=4..66.

Maple

q:= proc(n) option remember; nops(ifactors(n)[2])<2 end:
b:= proc(n, i, t) option remember; `if`(n=0,
      `if`(t=0, 1, 0), `if`(i<1 or t<1, 0, b(n, i-1, t)+
      `if`(q(i), b(n-i, min(n-i, i), t-1), 0)))
    end:
a:= n-> b(n$2, 4):
seq(a(n), n=4..66);  # Alois P. Heinz, Feb 05 2021

Mathematica

q[n_] := q[n] = Length[FactorInteger[n]] < 2;
b[n_, i_, t_] := b[n, i, t] = If[n == 0,
     If[t == 0, 1, 0], If[i < 1 || t < 1, 0, b[n, i - 1, t] +
     If[q[i], b[n - i, Min[n - i, i], t - 1], 0]]];
a[n_] := b[n, n, 4];
Table[a[n], {n, 4, 66}] (* Jean-François Alcover, Feb 22 2022, after Alois P. Heinz *)

Crossrefs

Cf. A000961, A010055, A071330, A341112, A341123, A341124, A341125, A341126, A341127.

Sequence in context: A325711 A306676 A363058 * A237825 A194939 A135635

Adjacent sequences: A341119 A341120 A341121 * A341123 A341124 A341125

Keyword

nonn

Author

Ilya Gutkovskiy, Feb 05 2021

Status

approved