A082570 a(1)=1, a(n)=ceiling(n*(a(n-1)+1/a(n-1))).

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

Links

Table of n, a(n) for n=1..22.

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

Adjacent sequences: A082567 A082568 A082569 * A082571 A082572 A082573

Keyword

nonn

Author

Benoit Cloitre, May 06 2003

Status

approved