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

1,4

Links

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

Formula

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

Prog

(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

Crossrefs

Cf. A032742, A353491, A353492.

Sequence in context: A172038 A331363 A359368 * A226131 A334318 A199056

Adjacent sequences: A353487 A353488 A353489 * A353491 A353492 A353493

Keyword

nonn

Author

Antti Karttunen, Apr 22 2022

Status

approved