OFFSET
0,2
LINKS
Geoffrey Critzer and Alois P. Heinz, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4, 13, 33, 61, 106, 157, 220, 277, 331, 364, 382, 369, 340, 289, 233, 170, 117, 70, 39, 17, 6).
FORMULA
G.f.: -(x+1) *(x^2+1) *(x^4+1) *(x^6+x^5+x^4+x^3+x^2+x+1) *(x^2+x+1) *(x^2-x+1) *(x^4+x^3+x^2+x+1) / (6*x^21 +17*x^20 +39*x^19 +70*x^18 +117*x^17 +170*x^16 +233*x^15 +289*x^14 +340*x^13 +369*x^12 +382*x^11 +364*x^10 +331*x^9 +277*x^8 +220*x^7 +157*x^6 +106*x^5 +61*x^4 +33*x^3 +13*x^2 +4*x-1).
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Geoffrey Critzer and Alois P. Heinz, May 19 2014
STATUS
approved