cp's OEIS Frontend

A341484 Number of ways to write n as an ordered sum of 7 nonprime numbers.

%I A341484 #7 Feb 13 2021 14:18:15
%S A341484 1,0,0,7,0,7,21,7,49,42,63,154,119,259,357,420,707,861,1169,1666,2072,
%T A341484 2752,3703,4557,5999,7637,9422,12089,14931,18354,22904,27825,33866,
%U A341484 41328,49539,59753,71386,85071,100800,119455,140448,164794,193179,224826,261464,303422
%N A341484 Number of ways to write n as an ordered sum of 7 nonprime numbers.
%p A341484 b:= proc(n, t) option remember;
%p A341484       `if`(n=0, `if`(t=0, 1, 0), `if`(t<1, 0, add(
%p A341484       `if`(isprime(j), 0, b(n-j, t-1)), j=1..n)))
%p A341484     end:
%p A341484 a:= n-> b(n, 7):
%p A341484 seq(a(n), n=7..52);  # _Alois P. Heinz_, Feb 13 2021
%t A341484 nmax = 52; CoefficientList[Series[Sum[Boole[!PrimeQ[k]] x^k, {k, 1, nmax}]^7, {x, 0, nmax}], x] // Drop[#, 7] &
%Y A341484 Cf. A005171, A018252, A052284, A076608, A340963, A341454, A341466, A341480, A341481, A341482, A341483, A341485, A341486.
%K A341484 nonn
%O A341484 7,4
%A A341484 _Ilya Gutkovskiy_, Feb 13 2021