A218379 Number of partitions of n into pentagonal parts.

1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 9, 9, 10, 11, 11, 13, 13, 14, 15, 15, 17, 17, 19, 21, 22, 24, 24, 26, 28, 29, 31, 31, 34, 36, 38, 41, 42, 45, 47, 50, 53, 54, 57, 59, 63, 67, 69, 73, 76, 80, 84, 87, 91, 94, 99, 103, 107, 112, 118, 124

Offset: 0

Author

Antonio Roldán, Oct 27 2012

Keywords

• nonn

Examples

			A(15)=5 because 15 = 12+1+1+1 = 5+5+5 = 5+5+1+1+1+1+1 = 5+1+1+1+1+1+1+1+1+1+1 = 1+1+1+1+1+1+1+1+1+1+1+1+1+1+1 with 12, 5, 1 pentagonal numbers.
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000 (terms 1..100 from Antonio Roldán)

Crossrefs

Cf. A000326, A095699.

Programs

PARI

{for (n=1, 100,p=truncate((1+sqrt(24*n+1))/6);m=polcoeff(prod(k=1,p,q=(3*k-1)*k/2;sum(h=0,truncate(n/q+1),x^(h*q))),n);write("B218379.txt",n," ",m))}

Extensions

a(0) = 1 prepended by Seiichi Manyama, Dec 09 2017