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

%I #12 May 30 2015 11:02:23

%S 2,3,8,32,160,960,6720,53760,483840,4838400,53222400,638668800,

%T 8302694400,116237721600,1743565824000,27897053184000,474249904128000,

%U 8536498274304000,162193467211776000,3243869344235520000

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

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

%F a(n) = A090802(n, n-3) for n > 2. - _Ross La Haye_, Sep 26 2005

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

%Y Equals 4 * A002301.

%K nonn

%O 1,1

%A _Benoit Cloitre_, May 06 2003