OFFSET
0,2
REFERENCES
S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (see p. 243, H*(3,5,n)).
LINKS
Chai Wah Wu, Table of n, a(n) for n = 0..10000
Index entries for linear recurrences with constant coefficients, signature (10,-45,120,-210,252,-210,120,-45,10,-1).
FORMULA
a(n) = 2*(n+1)*(n+2)^3*(n+3)*(n+4)*(25*n^3 + 142*n^2 + 295*n + 210)/8!.
G.f.: ( 1+26*x+133*x^2+195*x^3+86*x^4+9*x^5 )/(1-x)^10. - R. J. Mathar, Nov 01 2015
MAPLE
a:=n->(n+1)*(n+2)^3*(n+3)*(n+4)*(25*n^3+142*n^2+295*n+210)/20160: seq(a(n), n=0..27);
MATHEMATICA
CoefficientList[Series[(1+26*x+133*x^2+195*x^3+86*x^4+9*x^5)/(1-x)^10, {x, 0, 50}], x] (* G. C. Greubel, Sep 06 2017 *)
PROG
(Python)
A110693_list, m = [], [450, -816, 508, -121, 10, 1, 1, 1, 1, 1]
for _ in range(10001):
A110693_list.append(m[-1])
for i in range(9):
m[i+1] += m[i] # Chai Wah Wu, Jun 12 2016
(PARI) x='x+O(x^50); Vec((1+26*x+133*x^2+195*x^3+86*x^4+9*x^5)/(1-x)^10) \\ G. C. Greubel, Sep 06 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Emeric Deutsch, Aug 03 2005
STATUS
approved