A355914 - OEIS

%I #11 Sep 20 2022 00:49:08

%S 1,2,1,5,2,1,1,4,1,1,2,1,1,2,1,1,4,1,1,8,2,3,3,6,1,1,6,1,1,6,10,2,1,1,

%T 2,1,1,2,1,1,4,2,1,1,2,30,5,5,8,1,1,4,43,1,2,1,3,4,1,3,12,1,1,2,1,1,2,

%U 1,1,2,3,1,2,1,1,2,25,1,4,1,1,6,1,1,6

%N a(n) = gcd(b(n-1),b(n)), where b(n) = A351871(n).

%C In order to understand the difference between A351871 (which cycles) and A355898 (which appears to diverge), it would be helpful to understand the difference between the respective gcd sequences (this and A355899 - the latter has a very interesting graph!).

%H Michael S. Branicky, <a href="/A355914/b355914.txt">Table of n, a(n) for n = 2..10001</a>

%o (Python)

%o from math import gcd

%o from itertools import islice

%o def agen():

%o     a = [1, 2]

%o     while True: g = gcd(*a); yield g; a = [a[-1], g + sum(a)//g]

%o print(list(islice(agen(), 85))) # _Michael S. Branicky_, Sep 19 2022

%Y Cf. A351871, A355898, A355899.

%K nonn

%O 2,2

%A _N. J. A. Sloane_, Sep 19 2022

%E a(66) and beyond from _Michael S. Branicky_, Sep 19 2022