OFFSET
1,3
LINKS
Eric Weisstein's World of Mathematics, Maximal Clique
Eric Weisstein's World of Mathematics, Queen Graph
Index entries for linear recurrences with constant coefficients, signature (2, 1, -4, 1, 2, -1).
FORMULA
For n>3, a(n) = n*(73-3*(-1)^n+4*n*(2*n-3))/12-14.
For n>3, a(n) = 2*a(n-1)+a(n-2)-4*a(n-3)+a(n-4)+2*a(n-5)-a(n-6).
G.f.: -((x^2*(-1+x-7*x^2-19*x^3+3*x^4+22*x^5-9*x^6-10*x^7+4*x^8))/((-1+x)^4*(1+x)^2)).
MATHEMATICA
Table[Piecewise[{{1, n < 3}, {10, n == 3}}, n (73 - 3 (-1)^n + 4 n (2 n - 3))/12 - 14], {n, 20}]
Join[{1, 1}, LinearRecurrence[{2, 1, -4, 1, 2, -1}, {-28, -9, 10, 36, 76, 129}, {3, 20}]]
CoefficientList[Series[(1 - x + 7 x^2 + 19 x^3 - 3 x^4 - 22 x^5 + 9 x^6 + 10 x^7 - 4 x^8)/((-1 + x)^4 (1 + x)^2), {x, 0, 20}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Jun 20 2017
STATUS
approved