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 A107943 a(n) = (n+1)*(n+2)^2*(n+3)^2*(n+4)^2*(n+5)*(2n+3)/8640. 0
 1, 25, 245, 1470, 6468, 22932, 69300, 185130, 448305, 1002001, 2095093, 4140500, 7796880, 14080080, 24511824, 41314284, 67660425, 107991345, 168413245, 257188162, 385334180, 567352500, 822100500, 1173831750, 1653425865 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS KekulĂ© numbers for certain benzenoids. REFERENCES S. J. Cyvin and I. Gutman, KekulĂ© structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (p. 229). LINKS FORMULA G.f.: (1+15*x+40*x^2+25*x^3+3*x^4)/(1-x)^10. - Bruno Berselli, Apr 19 2011 MAPLE a:=n->(1/8640)*(n+1)*(n+2)^2*(n+3)^2*(n+4)^2*(n+5)*(2*n+3): seq(a(n), n=0..30); MATHEMATICA Table[((n+1)(n+2)^2(n+3)^2(n+4)^2(n+5)(2n+3))/8640, {n, 0, 30}]  (* Harvey P. Dale, Apr 19 2011 *) CROSSREFS Sequence in context: A108178 A278849 A294290 * A125388 A126546 A023073 Adjacent sequences:  A107940 A107941 A107942 * A107944 A107945 A107946 KEYWORD nonn AUTHOR Emeric Deutsch, Jun 12 2005 STATUS approved

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Last modified January 26 23:05 EST 2020. Contains 331289 sequences. (Running on oeis4.)