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A108676
a(n) = (n+1)^2*(n+2)*(5*n^2 + 15*n + 12)/24.
0
1, 16, 93, 340, 950, 2226, 4606, 8688, 15255, 25300, 40051, 60996, 89908, 128870, 180300, 246976, 332061, 439128, 572185, 735700, 934626, 1174426, 1461098, 1801200, 2201875, 2670876, 3216591, 3848068, 4575040, 5407950, 6357976
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. 231, # 37).
FORMULA
G.f.: (1 + 10*x + 12*x^2 + 2*x^3)/(1-x)^6.
MAPLE
a:=n->(n+1)^2*(n+2)*(5*n^2+15*n+12)/24: seq(a(n), n=0..36);
MATHEMATICA
Table[(n+1)^2(n+2)(5n^2+15n+12)/24, {n, 0, 30}] (* Harvey P. Dale, Apr 10 2022 *)
CROSSREFS
Sequence in context: A027938 A301527 A185458 * A304344 A316215 A305639
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Jun 17 2005
STATUS
approved