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A121954 a(0)=0, a(1)=1, a(n) = (n+1)*a(n-1) + a(n-2) for n>=2. 0
0, 1, 3, 13, 68, 420, 3015, 24541, 223884, 2263381, 25121075, 303716281, 3973432728, 55931774473, 842950049823, 13543132571641, 231076203767720, 4172914800390601, 79516457411189152, 1594502063024173568 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..19.

PROG

(PARI) a(n)=if(n<=1, n, (n + 1)*a(n - 1) + a(n - 2));

for(n=0, 22, print1(a(n), ", "));

CROSSREFS

Cf. A001053.

Sequence in context: A192737 A125279 A186371 * A058307 A020107 A284718

Adjacent sequences:  A121951 A121952 A121953 * A121955 A121956 A121957

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Sep 01 2006

STATUS

approved

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Last modified June 24 17:50 EDT 2019. Contains 324330 sequences. (Running on oeis4.)