A107917 a(n) = (n+1)(n+2)^2*(n+3)^3*(n+4)^2*(n+5)(n^2 + 6n + 10)/86400.

1, 34, 455, 3626, 20580, 91728, 340956, 1099890, 3166449, 8302294, 20131111, 45677996, 97894160, 199645824, 389817072, 732389580, 1329624009, 2340785370, 4008235231, 6693165094, 10923775940, 17459327600, 27374197500, 42166911150, 63900046665, 95377983246

Offset: 0

Author

Emeric Deutsch, Jun 12 2005

Keywords

• nonn
• easy

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

Programs

Maple

a:=n->(1/86400)*(n+1)*(n+2)^2*(n+3)^3*(n+4)^2*(n+5)*(n^2+6*n+10): seq(a(n),n=0..27);

Formula

G.f.: (x^6+22*x^5+113*x^4+190*x^3+113*x^2+22*x+1)/(x-1)^12. - Colin Barker, Jun 06 2012