A109119 a(n) = 2(5n^2 + 5n + 1)^3.

2, 2662, 59582, 453962, 2060602, 6885902, 18787862, 44376082, 94091762, 183467702, 334568302, 577609562, 952759082, 1512116062, 2321871302, 3464647202, 5042017762, 7177208582, 10017976862, 13739671402, 18548472602

Offset

0,1

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. 310).

Links

Table of n, a(n) for n=0..20.

Formula

G.f.: 2(1 + 1324z + 20495z^2 + 46360z^3 + 20495z^4 + 1324z^5 + z^6)/(1-z)^7.

a(n) = 2*A062786(n)^3. - R. J. Mathar, Jul 22 2022

Maple

a:=n->2*(5*n^2+5*n+1)^3: seq(a(n), n=0..28);

Crossrefs

Sequence in context: A347654 A324426 A114067 * A002495 A353126 A242109

Adjacent sequences: A109116 A109117 A109118 * A109120 A109121 A109122

Keyword

nonn,easy

Author

Emeric Deutsch, Jun 19 2005

Status

approved