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A082570
a(1)=1, a(n)=ceiling(n*(a(n-1)+1/a(n-1))).
0
1, 4, 13, 53, 266, 1597, 11180, 89441, 804970, 8049701, 88546712, 1062560545, 13813287086, 193386019205, 2900790288076, 46412644609217, 789014958356690, 14202269250420421, 269843115757988000, 5396862315159760001, 113334108618354960022, 2493350389603809120485
OFFSET
1,2
FORMULA
a(1)=1 and for n>1, a(n)=floor((e-1/2)*n!)
MATHEMATICA
Join[{a = 1}, Table[a = Ceiling[n*(a + 1/a)], {n, 2, 30}]]
PROG
(PARI) a(n)=if(n<2, 1, floor((exp(1)-1/2)*n!))
CROSSREFS
Sequence in context: A149466 A369226 A006604 * A145208 A149467 A149468
KEYWORD
nonn
AUTHOR
Benoit Cloitre, May 06 2003
STATUS
approved