OFFSET
1,2
COMMENTS
Lattice graphs are defined for n>=2; extended to n=1 using closed form.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
Eric Weisstein's World of Mathematics, Lattice Graph
Eric Weisstein's World of Mathematics, Molecular Topological Index
Index entries for linear recurrences with constant coefficients, signature (6,-15,20,-15,6,-1).
FORMULA
a(n) = 4*n^2*(n+1)*(n-1)^2.
a(n) = 48*A004302(n).
G.f.: 48*x^2*(1+6*x+3*x^2)/(1-x)^6. - Colin Barker, Aug 07 2012
E.g.f.: 4*x^2*(6 +18*x +9*x^2 +x^3)*exp(x). - G. C. Greubel, Jan 04 2019
MATHEMATICA
Table[4*n^2*(n+1)*(n-1)^2, {n, 1, 30}] (* G. C. Greubel, Jan 04 2019 *)
PROG
(PARI) vector(30, n, 4*n^2*(n+1)*(n-1)^2) \\ G. C. Greubel, Jan 04 2019
(Magma) [4*n^2*(n+1)*(n-1)^2: n in [1..30]]; // G. C. Greubel, Jan 04 2019
(Sage) [4*n^2*(n+1)*(n-1)^2 for n in (1..30)] # G. C. Greubel, Jan 04 2019
(GAP) List([0..30], n -> 4*n^2*(n+1)*(n-1)^2); # G. C. Greubel, Jan 04 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Jul 11 2011
STATUS
approved