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A176638
Partial sums of A018190.
0
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
1,2
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.
FORMULA
a(n) = SUM[i=1..n] A018190(i).
EXAMPLE
a(6) = 1 + 1 + 3 + 7 + 22 + 81 = 115.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Apr 22 2010
STATUS
approved