login
A192846
Molecular topological indices of the sunlet graphs.
1
14, 56, 126, 256, 430, 696, 1022, 1472, 1998, 2680, 3454, 4416, 5486, 6776, 8190, 9856, 11662, 13752, 15998, 18560, 21294, 24376, 27646, 31296, 35150, 39416, 43902, 48832, 53998, 59640
OFFSET
1,1
COMMENTS
Sunlet graphs are defined for n>=3; extended to n=1 using closed form.
LINKS
Eric Weisstein's World of Mathematics, Molecular Topological Index
Eric Weisstein's World of Mathematics, Sun Graph
FORMULA
a(n) = n*(2*n*(n+3)+(-1)^n+7).
G.f.: 2*x*(x^4+2*x^3+14*x+7)/((x-1)^4*(x+1)^2). - Colin Barker, Aug 07 2012
E.g.f.: x*((15 + 12*x + 2*x^2)*exp(x) - exp(-x)). - G. C. Greubel, Jan 05 2019
MATHEMATICA
Table[n*(2*n*(n+3)+(-1)^n+7), {n, 1, 40}] (* G. C. Greubel, Jan 05 2019 *)
PROG
(PARI) vector(40, n, n*(2*n*(n+3)+(-1)^n+7)) \\ G. C. Greubel, Jan 05 2019
(Magma) [n*(2*n*(n+3)+(-1)^n+7): n in [1..40]]; // G. C. Greubel, Jan 05 2019
(Sage) [n*(2*n*(n+3)+(-1)^n+7) for n in (1..40)] # G. C. Greubel, Jan 05 2019
(GAP) List([1..40], n -> n*(2*n*(n+3)+(-1)^n+7)); # G. C. Greubel, Jan 05 2019
CROSSREFS
Sequence in context: A022285 A100157 A144555 * A212347 A115129 A281200
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jul 11 2011
STATUS
approved