A381508 - OEIS

%I #40 Apr 26 2025 10:25:06

%S 1,7,728,14,208,728,342,28,2184,1456,354312,728,9520,2394,1456,56,

%T 709928,2184,5227320,1456,124488,354312,279840,728,1040,9520,6552,

%U 2394,243880,1456,71040,112,4606056,4969496,35568,2184,20362908,5227320,123760,1456,201840

%N Pisano period of Hexanacci numbers (A001592) mod n.

%H Chai Wah Wu, <a href="/A381508/b381508.txt">Table of n, a(n) for n = 1..222</a>

%H Martin Guerra and Doron Zeilberger, <a href="http://sites.math.rutgers.edu/~zeilberg/tokhniot/PisanoP.txt">Maple program</a>

%p # load programs from linked file:

%p seq(Pis([[0$5, 1],[1$6]],n,400000), n=1..16);

%o (Python)

%o from math import lcm

%o from functools import lru_cache

%o from sympy import factorint

%o @lru_cache(maxsize=None)

%o def A381508(n):

%o     if n == 1:

%o         return 1

%o     f = factorint(n).items()

%o     if len(f) > 1:

%o         return lcm(*(A381508(a**b) for a,b in f))

%o     else:

%o         k, x = 1, (0,0,0,0,1,1)

%o         while x != (0,0,0,0,0,1):

%o             k += 1

%o             x = x[1:]+(sum(x) % n,)

%o         return k # _Chai Wah Wu_, Apr 25 2025

%Y Cf. A001175, A001592.

%K nonn

%O 1,2

%A _Martin Guerra_ and _Doron Zeilberger_, Apr 24 2025

%E a(17)-a(41) from _Alois P. Heinz_, Apr 25 2025