A176638 Partial sums of A018190.

1, 2, 5, 12, 34, 115, 446, 1881, 8386, 38472, 179701, 849285, 4047541, 19415118, 93623028, 453486806, 2205081449, 10758731196, 52651373968, 258365785954, 1270930958357, 6265738653554, 30952863554094, 153191072337297

Offset: 1

Author

Jonathan Vos Post, Apr 22 2010

Keywords

• nonn

Comments

Partial sums of number of planar simply-connected polyhexes (or benzenoid hydrocarbons) with n hexagons. The only known primes in the partial sum are 2 and 5.

Examples

			a(6) = 1 + 1 + 3 + 7 + 22 + 81 = 115.
		

Crossrefs

Cf. A000228, A002216, A018190, A038142-A038147.

Formula

a(n) = SUM[i=1..n] A018190(i).