OFFSET
1,2
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,1,-1).
FORMULA
j(1)=1, j(2)=11; then j(n)=j(n-2)+13.
a(n) = (-15+7*(-1)^n+26*n)/4. G.f.: x*(2*x^2+10*x+1) / ((x-1)^2*(x+1)). - Colin Barker, Apr 16 2014
MATHEMATICA
fQ[n_] := IntegerQ[(6n(n + 1) + 1)/13]; Select[ Range[ 361], fQ[ # ] &] (* Robert G. Wilson v, May 02 2005 *)
LinearRecurrence[{1, 1, -1}, {1, 11, 14}, 60] (* Harvey P. Dale, Jun 07 2016 *)
PROG
(PARI) Vec((2*x^2+10*x+1)/((x-1)^2*(x+1)) + O(x^100)) \\ Colin Barker, Apr 16 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Pierre CAMI, May 01 2005
EXTENSIONS
More terms from Robert G. Wilson v, May 02 2005
STATUS
approved