OFFSET
2,2
LINKS
Heinrich Ludwig, Table of n, a(n) for n = 2..1000
Index entries for linear recurrences with constant coefficients, signature (3,1,-11,6,14,-14,-6,11,-1,-3,1).
FORMULA
a(n) = (n^6 - 27*n^4 + 80*n^3 + 158*n^2 - 1028*n + 1200 + (1 - (-1)^n)/2*(8*n^3 - 9*n^2 - 44*n + 45))/48 for n >= 4.
G.f.: -25 - 8*x + 3*x^3 + (25 - 67*x - 48*x^2 + 270*x^3 - 41*x^4 - 318*x^5 + 291*x^6 + 354*x^7 - 188*x^8 - 87*x^9 + 49*x^10) / ((1-x)^7*(1+x)^4). - Vaclav Kotesovec, Jun 19 2014
MATHEMATICA
Drop[CoefficientList[Series[-25 - 8*x + 3*x^3 + (25 - 67*x - 48*x^2 + 270*x^3 - 41*x^4 - 318*x^5 + 291*x^6 + 354*x^7 - 188*x^8 - 87*x^9 + 49*x^10) / ((1-x)^7*(1+x)^4), {x, 0, 20}], x], 2] (* Vaclav Kotesovec, Jun 19 2014 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Heinrich Ludwig, Jun 19 2014
STATUS
approved