OFFSET
0,2
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
A. J. Guttmann, Indicators of solvability for lattice models, Discrete Math., 217 (2000), 167-189 (H_4(1)/2 of Section 3).
Index entries for linear recurrences with constant coefficients, signature (2,2,-6,0,6,-2,-2,1).
FORMULA
G.f.: (1 +14*x +56*x^2 +122*x^3 +146*x^4 +122*x^5 +56*x^6 +14*x^7 +x^8) / ((1 -x)^5*(1 +x)^3).
From Colin Barker, Dec 10 2016: (Start)
a(n) = (133*n^4 + 524*n^2 + 96)/48 for n>0 and even.
a(n) = (133*n^4 + 542*n^2 + 93)/48 for n odd.
(End)
MATHEMATICA
LinearRecurrence[{2, 2, -6, 0, 6, -2, -2, 1}, {1, 16, 90, 328, 886, 2016, 3986, 7208, 12050}, 40] (* Harvey P. Dale, Oct 08 2017 *)
PROG
(PARI) Vec((1 +14*x +56*x^2 +122*x^3 +146*x^4 +122*x^5 +56*x^6 +14*x^7 +x^8)/((1 -x)^5*(1 +x)^3) + O(x^50)) \\ Colin Barker, Dec 10 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Christian G. Bower, Jun 19 2000
STATUS
approved