OFFSET
0,2
LINKS
Bruno Berselli, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
G.f.: (1+x)*(1+13*x+x^2)/(1-x)^3. - Bruno Berselli, Feb 06 2012
E.g.f.: (x*(x+1)*15+2)*e^x-1. - Gopinath A. R., Feb 14 2012
Sum_{n>=0} 1/a(n) = 3/4+sqrt(30)/60*Pi*coth(Pi *sqrt(30)/15) = 1.101107302494... - R. J. Mathar, May 07 2024
MATHEMATICA
Join[{1}, 15 Range[42]^2 + 2] (* Bruno Berselli, Feb 06 2012 *)
Join[{1}, LinearRecurrence[{3, -3, 1}, {17, 62, 137}, 50]] (* Vincenzo Librandi, Aug 03 2015 *)
PROG
(PARI) A010005(n)=15*n^2+2-!n \\ M. F. Hasler, Feb 14 2012
(Magma) [1] cat [15*n^2+2: n in [1..50]]; // Vincenzo Librandi, Aug 03 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Bruno Berselli, Feb 06 2012
STATUS
approved