A004168 a(n+1) = a(n)*(a(n)+1).

3, 12, 156, 24492, 599882556, 359859081592975692, 129498558604939936868397356895854556, 16769876680757063368089314196389622249367851612542961252860614401811692

Offset

0,1

Comments

The next term (a(8)) has 141 digits. - Harvey P. Dale, Jul 02 2021

Links

Table of n, a(n) for n=0..7.

Formula

a(n) = A082732(n+3) - 1. - Max Alekseyev, Aug 09 2019

Maple

A004168 := proc(n) option remember; if n=0 then 3 else A004168(n-1)*(A004168(n-1)+1); fi; end;

Mathematica

a = {3}; Do[AppendTo[a, a[[n - 1]] (a[[n - 1]] + 1)], {n, 2, 8}]; a (* Michael De Vlieger, Feb 23 2016 *)
NestList[#(#+1)&, 3, 7] (* Harvey P. Dale, Jul 02 2021 *)

Prog

(Magma) [n eq 1 select 3 else  Self(n-1)*(Self(n-1)+1): n in [1..10]]; // Vincenzo Librandi, Feb 23 2016

Crossrefs

Cf. A000058, A007018.

Sequence in context: A098152 A028301 A356719 * A301650 A061960 A120606

Adjacent sequences: A004165 A004166 A004167 * A004169 A004170 A004171

Keyword

nonn,easy

Author

N. J. A. Sloane

Extensions

a(7) from Vincenzo Librandi, Feb 23 2016

Status

approved