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A109118
a(n) = 2*(n^2 + 3*n + 1)^3.
1
2, 250, 2662, 13718, 48778, 137842, 332750, 715822, 1409938, 2590058, 4496182, 7447750, 11859482, 18258658, 27303838, 39805022, 56745250, 79303642, 108879878, 147120118, 195944362, 257575250, 334568302, 429843598, 546718898
OFFSET
0,1
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.: 2*(1 + 118*z + 477*z^2 + 132*z^3 - 13*z^4 + 6*z^5 - z^6)/(1-z)^7.
MAPLE
A109118:=n->2*(n^2+3*n+1)^3: seq(A109118(n), n=0..30);
MATHEMATICA
Table[2 (n^2 + 3 n + 1)^3, {n, 0, 30}] (* Wesley Ivan Hurt, Feb 04 2017 *)
CROSSREFS
Cf. A028387.
Sequence in context: A024349 A012529 A012527 * A034313 A177320 A304211
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jun 19 2005
STATUS
approved