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

Author

Benoit Cloitre, May 06 2003

Keywords

• nonn

Crossrefs

Equals 4 * A002301.

Programs

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 *)

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