A366510 Largest prime divisor of n which is < sqrt(n), 1 if n is prime, square of prime or 1.

1, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 5, 1, 2, 3, 2, 5, 3, 1, 2, 3, 5, 1, 3, 1, 2, 5, 2, 1, 3, 1, 5, 3, 2, 1, 3, 5, 7, 3, 2, 1, 5, 1, 2, 7, 2, 5, 3, 1, 2, 3, 7, 1, 3, 1, 2, 5, 2, 7, 3, 1, 5, 3, 2, 1, 7, 5, 2, 3, 2, 1, 5, 7, 2, 3, 2, 5, 3, 1, 7, 3, 5

Offset: 1

Author

Ilya Gutkovskiy, Oct 11 2023

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A006530, A060775, A085392, A217581.

Programs

PARI

a(n) = {my(m=1); foreach(factor(n)[,1], d, if(d^2 < n, m=max(m,d))); m} \\ Andrew Howroyd, Oct 11 2023