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A074703
a(n) = n^2*a(n-1)+1, a(1)=0.
1
0, 1, 10, 161, 4026, 144937, 7101914, 454522497, 36816322258, 3681632225801, 445477499321922, 64148759902356769, 10841140423498293962, 2124863523005665616553, 478094292676274763724426
OFFSET
1,3
LINKS
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
Sequence in context: A090374 A034724 A234283 * A374423 A190903 A303486
KEYWORD
easy,nonn
AUTHOR
Vladeta Jovovic, Sep 03 2002
STATUS
approved