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 A107941 a(n) = (n+1)(n+2)^2*(n+3)^2*(n+4)^2*(n+5)(3n^2 + 13n + 15)/43200. 1
 1, 31, 371, 2646, 13524, 54684, 185724, 551034, 1467609, 3578575, 8107099, 17257604, 34826064, 67098864, 124140528, 221594796, 383151321, 643861911, 1054526011, 1687405258, 2643571700, 4062243900, 6132519900, 9107976150, 13324667265, 19223133111, 27375097491 (list; graph; refs; listen; history; text; internal format)
 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. 229). LINKS T. D. Noe, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (11,-55,165,-330,462,-462,330,-165,55,-11,1). FORMULA G.f.: (1+20*x+85*x^2+105*x^3+38*x^4+3*x^5)/(1-x)^11. - Colin Barker, Sep 18 2012 MAPLE a:=n->(1/43200)*(n+1)*(n+2)^2*(n+3)^2*(n+4)^2*(n+5)*(3*n^2+13*n+15): seq(a(n), n=0..28); CROSSREFS Sequence in context: A138440 A307008 A161347 * A142684 A042868 A258944 Adjacent sequences: A107938 A107939 A107940 * A107942 A107943 A107944 KEYWORD nonn,easy AUTHOR Emeric Deutsch, Jun 12 2005 STATUS approved

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Last modified June 20 08:07 EDT 2024. Contains 373512 sequences. (Running on oeis4.)