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A109117
a(n) = (n+1)^3*(2n+1)(5n+1).
0
1, 144, 1485, 7168, 23625, 61776, 138229, 276480, 508113, 874000, 1425501, 2225664, 3350425, 4889808, 6949125, 9650176, 13132449, 17554320, 23094253, 29952000, 38349801, 48533584, 60774165, 75368448, 92640625, 112943376
OFFSET
0,2
COMMENTS
Kekulé numbers for certain benzenoids.
REFERENCES
S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 310).
FORMULA
G.f.: (1 + 138z + 636z^2 + 398z^3 + 27z^4)/(1-z)^6.
MAPLE
a:=n->(n+1)^3*(2*n+1)*(5*n+1): seq(a(n), n=0..30);
MATHEMATICA
Table[(2n + 1)(5n + 1)(n + 1)^3, {n, 0, 30}] (* Wesley Ivan Hurt, Jan 24 2014 *)
CROSSREFS
Sequence in context: A223435 A169859 A137416 * A209205 A223594 A223445
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jun 19 2005
STATUS
approved