OFFSET
1,3
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..253
FORMULA
a(n) = round(n!^2*(BesselI(0, 2)-2)).
MATHEMATICA
nxt[{n_, a_}]:={n+1, (n+1)^2 a+1}; Transpose[NestList[nxt, {1, 0}, 20]][[2]] (* Harvey P. Dale, Dec 11 2013 *)
PROG
(PARI) a(n)=round((besseli(0, 2)-2)*n!^2) \\ Charles R Greathouse IV, Feb 19 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Sep 03 2002
STATUS
approved