A074703 a(n) = n^2*a(n-1)+1, a(1)=0.

0, 1, 10, 161, 4026, 144937, 7101914, 454522497, 36816322258, 3681632225801, 445477499321922, 64148759902356769, 10841140423498293962, 2124863523005665616553, 478094292676274763724426

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

Cf. A006040, A073701.

Sequence in context: A090374 A034724 A234283 * A190903 A303486 A064747

Adjacent sequences: A074700 A074701 A074702 * A074704 A074705 A074706

Keyword

easy,nonn

Author

Vladeta Jovovic, Sep 03 2002

Status

approved