OFFSET
1,2
LINKS
Colin Barker, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,2,0,-1).
FORMULA
a(n) = (14*n+12*n*(-1)^n+1 + (-1)^(n-1))/4 for n>1.
From Colin Barker, Jan 02 2017: (Start)
a(n) = 2*a(n-2) - a(n-4) for n>4.
G.f.: x*(1+13*x) / ((1-x)^2*(1+x)^2).
(End)
MATHEMATICA
Table[{n, 13n}, {n, 50}]//Flatten (* or *) LinearRecurrence[{0, 2, 0, -1}, {1, 13, 2, 26}, 100] (* Harvey P. Dale, Oct 16 2019 *)
PROG
(PARI) Vec(x*(1+13*x) / ((1-x)^2*(1+x)^2) + O(x^30)) \\ Colin Barker, Jan 02 2017
CROSSREFS
KEYWORD
nonn,tabf,easy
AUTHOR
Vincenzo Librandi, Apr 23 2010
EXTENSIONS
Partially edited by N. J. A. Sloane, Jun 23 2010
STATUS
approved