OFFSET
0,1
LINKS
Patrick De Geest, Palindromic Quasi_Over_Squares of the form n^2+(n+X)
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = A176271(n + 1, 3) for n > 1. - Reinhard Zumkeller, Apr 13 2010
a(n) = 2*n + a(n-1) for n>0, a(0)=5. - Vincenzo Librandi, Aug 05 2010
From Ilya Gutkovskiy, Nov 25 2016: (Start)
G.f.: (5 - 8*x + 5*x^2)/(1 - x)^3.
Sum_{n>=0} 1/a(n) = Pi*tanh(sqrt(19)*Pi/2)/sqrt(19) = 0.720729156259... (End)
MAPLE
with (combinat):seq(fibonacci(3, n)+n+4, n=0..47); # Zerinvary Lajos, Jun 07 2008
MATHEMATICA
Table[n^2 + n + 5, {n, 0, 100}] (* T. D. Noe, Oct 29 2009 *)
PROG
(PARI) a(n)=n^2+n+5 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Corrected by T. D. Noe, Nov 09 2006
Definition and offset fixed by Franklin T. Adams-Watters, Jul 06 2009
STATUS
approved