OFFSET
2,1
LINKS
Colin Barker, Table of n, a(n) for n = 2..1000
Eric Weisstein's World of Mathematics, Crossed Prism Graph
Eric Weisstein's World of Mathematics, Hamiltonian Path
Index entries for linear recurrences with constant coefficients, signature (6,-12,8).
FORMULA
a(n) = A137885(n)/2.
From Colin Barker, Jul 19 2019: (Start)
G.f.: 24*x^2*(3 - 6*x + 4*x^2) / (1 - 2*x)^3.
a(n) = 3*2^n*n*(1+n).
a(n) = 6*a(n-1) - 12*a(n-2) + 8*a(n-3) for n>4.
(End)
PROG
(PARI) Vec(24*x^2*(3 - 6*x + 4*x^2) / (1 - 2*x)^3 + O(x^30)) \\ Colin Barker, Jul 19 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, May 14 2019
STATUS
approved