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A192836 Molecular topological indices of the pan graphs. 1
14, 29, 48, 83, 126, 193, 272, 383, 510, 677, 864, 1099, 1358, 1673, 2016, 2423, 2862, 3373, 3920, 4547, 5214, 5969, 6768, 7663, 8606, 9653, 10752, 11963, 13230, 14617, 16064, 17639, 19278, 21053, 22896, 24883, 26942, 29153, 31440, 33887, 36414, 39109, 41888 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Pan graphs are defined for n>=3; extended to n=1 using closed form.

LINKS

Colin Barker, Table of n, a(n) for n = 1..1000

Eric Weisstein's World of Mathematics, Molecular Topological Index

Index entries for linear recurrences with constant coefficients, signature (2,1,-4,1,2,-1).

FORMULA

a(n) = (1/4)*(26+27*n+4*n^2+2*n^3+(-1)^n*(2+n)).

G.f. -x*(7*x^5-14*x^4-14*x^3+24*x^2-x-14)/((x-1)^4*(x+1)^2). - Colin Barker, Aug 07 2012

PROG

(PARI) Vec(-x*(7*x^5-14*x^4-14*x^3+24*x^2-x-14) / ((x-1)^4*(x+1)^2) + O(x^100)) \\ Colin Barker, Jan 23 2017

CROSSREFS

Sequence in context: A257645 A046045 A132756 * A124681 A195145 A263119

Adjacent sequences:  A192833 A192834 A192835 * A192837 A192838 A192839

KEYWORD

nonn,easy

AUTHOR

Eric W. Weisstein, Jul 11 2011

STATUS

approved

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Last modified November 20 08:16 EST 2018. Contains 317385 sequences. (Running on oeis4.)