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A192790 Molecular topological index of the Andrásfai graphs. 0
4, 80, 336, 880, 1820, 3264, 5320, 8096, 11700, 16240, 21824, 28560, 36556, 45920, 56760, 69184, 83300, 99216, 117040, 136880, 158844, 183040, 209576, 238560, 270100, 304304, 341280, 381136, 423980, 469920 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Andrásfai Graph
Eric Weisstein's World of Mathematics, Molecular Topological Index
FORMULA
a(n) = 2*n*(3*n-2)*(3*n-1).
a(n) = 4*A006566(n).
a(n) = +4*a(n-1) -6*a(n-2) +4*a(n-3) -1*a(n-4).
G.f.: 4*x*(1+16*x+10*x^2) / (x-1)^4 . - R. J. Mathar, May 06 2014
MATHEMATICA
LinearRecurrence[{4, -6, 4, -1}, {4, 80, 336, 880}, 30] (* Harvey P. Dale, Jan 31 2013 *)
CROSSREFS
Sequence in context: A216410 A125710 A204296 * A211152 A093854 A345459
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jul 10 2011
STATUS
approved

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Last modified June 24 06:34 EDT 2024. Contains 373663 sequences. (Running on oeis4.)