A067691 - OEIS

%I #8 Feb 05 2021 03:51:33

%S 0,1,2,9,1000,1004006004001,

%T 1020191144865623440455270145683555422808365843606721760320032

%N a(n) = (a(n-1) + 1)^(n-1) for n > 0, a(0) = 0.

%C a(7) has 361 digits.

%e Given a(3) = 9: a(4) = (a(4-1)+1)^(4-1) = (9+1)^3 = 1000.

%o (PARI) a(n) = if (n==0, 0, (a(n-1) + 1)^(n-1)); \\ _Michel Marcus_, Feb 05 2021

%Y Cf. A004019.

%K nonn

%O 0,3

%A _Reinhard Zumkeller_, Feb 04 2002