OFFSET
1,1
COMMENTS
Here m = (11*(2*n-1) - (-1)^n)/4 for n > 0.
LINKS
B. Berselli, Table of n, a(n) for n = 1..10000.
Index entries for linear recurrences with constant coefficients, signature (1,2,-2,-1,1).
FORMULA
a(n) = (66*n*(n-1) - 3*(2*n-1)*(-1)^n + 17)/4.
G.f.: x*(5 + 30*x + 62*x^2 + 30*x^3 + 5*x^4)/((1+x)^2*(1-x)^3).
a(n) = a(-n+1) = a(n-1) + 2*a(n-2) - 2*a(n-3) - a(n-4) + a(n-5).
MATHEMATICA
LinearRecurrence[{1, 2, -2, -1, 1}, {5, 35, 107, 197, 341}, 40] (* Vincenzo Librandi, Nov 16 2011 *)
PROG
(Magma) [(66*n*(n-1)-3*(2*n-1)*(-1)^n+17)/4: n in [1..40]]; // Vincenzo Librandi, Nov 16 2011
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Bruno Berselli, Jul 11 2010
STATUS
approved