A353490 The largest proper divisor of n, reduced modulo 4, with a(1) = 1.

1, 1, 1, 2, 1, 3, 1, 0, 3, 1, 1, 2, 1, 3, 1, 0, 1, 1, 1, 2, 3, 3, 1, 0, 1, 1, 1, 2, 1, 3, 1, 0, 3, 1, 3, 2, 1, 3, 1, 0, 1, 1, 1, 2, 3, 3, 1, 0, 3, 1, 1, 2, 1, 3, 3, 0, 3, 1, 1, 2, 1, 3, 1, 0, 1, 1, 1, 2, 3, 3, 1, 0, 1, 1, 1, 2, 3, 3, 1, 0, 3, 1, 1, 2, 1, 3, 1, 0, 1, 1, 1, 2, 3, 3, 3, 0, 1, 1, 1, 2, 1, 3, 1, 0, 3

Offset: 1

Author

Antti Karttunen, Apr 22 2022

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537

Crossrefs

Cf. A032742, A353491, A353492.

Programs

PARI

A032742(n) = if(1==n,n,n/vecmin(factor(n)[,1]));
A353490(n) = (A032742(n)%4);

Python

from sympy import factorint
def a(n): return 1 if n==1 else (n//min(factorint(n)))%4
print([a(n) for n in range(1, 106)]) # Michael S. Branicky, Apr 26 2022

Formula

a(n) = A010873(A032742(n)).