A082569 a(1)=2; a(n)=ceiling(n*(a(n-1)-1/a(n-1))).

2, 3, 8, 32, 160, 960, 6720, 53760, 483840, 4838400, 53222400, 638668800, 8302694400, 116237721600, 1743565824000, 27897053184000, 474249904128000, 8536498274304000, 162193467211776000, 3243869344235520000

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Formula

a(1)=2 a(2)=3 and for n>2, a(n)= 4*n!/3.

a(n) = A090802(n, n-3) for n > 2. - Ross La Haye, Sep 26 2005

Mathematica

nxt[{n_, a_}]:={n+1, Ceiling[(n+1)(a-1/a)]}; Transpose[NestList[nxt, {1, 2}, 20]][[2]] (* Harvey P. Dale, May 30 2015 *)

Crossrefs

Equals 4 * A002301.

Sequence in context: A340935 A162074 A162052 * A340495 A084908 A078742

Adjacent sequences: A082566 A082567 A082568 * A082570 A082571 A082572

Keyword

nonn

Author

Benoit Cloitre, May 06 2003

Status

approved