A376767 - OEIS

%I #10 Dec 16 2024 08:48:04

%S 1,5,55,12155,295500205,349281484915668305,

%T 243995111409788451714836854478814355,

%U 238134457567500314773144369878965950377595240310563734057802960695078455

%N a(1) = 1; thereafter, a(n) = c*a(n-1)^2 + a(n-1), where c=4 if n is even, c=2 if n is odd.

%C Used to construct A376768.

%H Paolo Xausa, <a href="/A376767/b376767.txt">Table of n, a(n) for n = 1..11</a>

%e a(3) = 2*a(2)^2 + a(2) = 55.

%t Module[{n = 1}, NestList[If[OddQ[++n], 2, 4]*#^2 + # &, 1, 8]] (* _Paolo Xausa_, Dec 16 2024 *)

%Y Cf. A376768.

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Nov 03 2024