A333974 - OEIS

%I #21 Nov 19 2023 21:17:23

%S 1,3,4,3,7,12,5,3,8,21,6,12,15,15,28,3,31,24,23,21,20,6,13,12,28,15,

%T 24,15,46,84,7,3,12,93,35,24,20,69,60,21,25,60,44,6,56,39,14,12,30,84,

%U 124,15,84,24,42,15,92,138,11,84,117,21,40,3,105,12,121,93

%N Eventual period of A007660 modulo n.

%C Multiplicative: If n = p^x * q^y * ... for distinct primes p,q,... then a(n) = a(p^x) * a(q^y) * ...

%H David A. Corneth, <a href="/A333974/a333974.gp.txt">PARI program</a>.

%F a(n) | a(k*n), k=2,3,...

%e a(1) is trivially 1.

%e For n=2 the sequence is 0, {0,1,1}, {0,1,1}, hence a(2) = 3.

%e For n=3 the sequence is 0, {0,1,1,2}, {0,1,1,2}, hence a(3) = 4.

%e For n=4 the sequence is 0,0,1,1, {2,3,3}, {2,3,3}, hence a(4) = 3.

%e For n=5 the sequence is 0, {0,1,1,2,3,2,2}, {0,1,1,2,3,2,2}, hence a(5) = 7.

%o (PARI) See Corneth link \\ _David A. Corneth_, Sep 04 2020

%K nonn,mult

%O 1,2

%A _Isaac Kaufmann_, Sep 03 2020

%E More terms from _Jinyuan Wang_, Sep 04 2020