This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A356550 #5 Aug 15 2022 05:19:56
%S A356550 1,4,12,24,60,12,24,24,24,60,60,24,48,24,60,24,24,24,24,120,24,60,24,
%T A356550 24,300,48,24,24,48,60,120,24,60,24,120,24,18,24,48,120,60,24,60,120,
%U A356550 120,24,48,24,48,300,24,48,72,24,60,24,24,48,42,120,120,120,24
%N A356550 a(n) is the period of {F(F(k)) mod n, k >= 0}, where F denotes the Fibonacci numbers (A000045).
%C A356550 F(F(k)) mod n = F(F(k mod pi(pi(n))) mod pi(n)) mod n (where pi = A001175), so F(F(k)) mod n is periodic and the sequence is well defined.
%H A356550 Rémy Sigrist, <a href="/A356550/a356550.gp.txt">PARI program</a>
%F A356550 a(n) divides A001175(A001175(n)).
%e A356550 For n = 6:
%e A356550 - A001175(A001175(6)) = A001175(24) = 24,
%e A356550 - the values of F(F(k)) mod 6 for k = 0..23 are:
%e A356550 0, 1, 1, 1, 2, 5, 3, 5, 2, 1, 1, 1, 0, 1, 1, 1, 2, 5, 3, 5, 2, 1, 1, 1
%e A356550 - we see that F(F(k)) mod 6 = F(F(k+12)) mod 6,
%e A356550 - so a(6) = 12.
%o A356550 (PARI) See Links section.
%Y A356550 Cf. A000045, A001175, A007570.
%K A356550 nonn
%O A356550 1,2
%A A356550 _Rémy Sigrist_, Aug 11 2022