A192491 Molecular topological indices of the complete tripartite graphs K_{n,n,n}.

24, 240, 864, 2112, 4200, 7344, 11760, 17664, 25272, 34800, 46464, 60480, 77064, 96432, 118800, 144384, 173400, 206064, 242592, 283200, 328104, 377520, 431664, 490752, 555000, 624624, 699840, 780864, 867912, 961200

Offset

1,1

Links

Table of n, a(n) for n=1..30.

Eric Weisstein's World of Mathematics, Complete Tripartite Graph

Eric Weisstein's World of Mathematics, Molecular Topological Index

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Formula

a(n) = 12*n^2*(3*n-1).

a(n) = 24*A050509(n).

G.f.: 24*x*(2*x^2+6*x+1)/(x-1)^4. [Colin Barker, Nov 04 2012]

From Bruce J. Nicholson, Sep 18 2019: (Start)

a(n) = 24*n * A000326(n).

a(n) = 4*n^2 * A017233(n).

a(n) = 24*(n^3 + A000292(n-2) + A000330(n-2)).

a(n) = 24*(n^4 - (A008585(n) * A000330(n-1))).

a(n) = 6*A046092(n) + (A008594(n+1) * A140676(n-1)). (End)

Crossrefs

Cf. A000326, A000330, A000292, A017233, A008594, A140676, A046092.

Sequence in context: A006863 A335128 A052663 * A167548 A192849 A253285

Adjacent sequences: A192488 A192489 A192490 * A192492 A192493 A192494

Keyword

nonn,easy

Author

Eric W. Weisstein, Jul 10 2011

Status

approved