OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,1,-1).
FORMULA
a(n) = -3*(4+(-1)^n) + 10*n.
a(n) = a(n-1) + a(n-2) - a(n-3).
G.f.: x*(15*x^2+4*x+1) / ((x-1)^2*(x+1)).
E.g.f.: 15 + (10*x - 12)*exp(x) - 3*exp(-x). - David Lovler, Sep 05 2022
MATHEMATICA
Flatten[Table[20n + {1, 5}, {n, 0, 24}]] (* Alonso del Arte, Aug 12 2013 *)
PROG
(PARI) Vec(x*(15*x^2+4*x+1)/((x-1)^2*(x+1)) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Aug 12 2013
STATUS
approved