cp's OEIS Frontend

A341486 Number of ways to write n as an ordered sum of 9 nonprime numbers.

%I A341486 #6 Feb 13 2021 14:19:54
%S A341486 1,0,0,9,0,9,36,9,81,93,108,333,270,585,945,1047,2016,2547,3612,5571,
%T A341486 7101,10227,14256,18621,25830,34497,44955,60610,78480,101754,133092,
%U A341486 169380,217008,276852,347967,439272,549786,683244,849528,1047678,1288017,1577934
%N A341486 Number of ways to write n as an ordered sum of 9 nonprime numbers.
%p A341486 b:= proc(n, t) option remember;
%p A341486       `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add(
%p A341486       `if`(isprime(j), 0, b(n-j, t-1)), j=1..n)))
%p A341486     end:
%p A341486 a:= n-> b(n, 9):
%p A341486 seq(a(n), n=9..50);  # _Alois P. Heinz_, Feb 13 2021
%t A341486 nmax = 50; CoefficientList[Series[Sum[Boole[!PrimeQ[k]] x^k, {k, 1, nmax}]^9, {x, 0, nmax}], x] // Drop[#, 9] &
%Y A341486 Cf. A005171, A018252, A052284, A076608, A340965, A341457, A341468, A341480, A341481, A341482, A341483, A341484, A341485.
%K A341486 nonn
%O A341486 9,4
%A A341486 _Ilya Gutkovskiy_, Feb 13 2021