A160696 Largest k such that k^2 divides prime(n)+1.

1, 2, 1, 2, 2, 1, 3, 2, 2, 1, 4, 1, 1, 2, 4, 3, 2, 1, 2, 6, 1, 4, 2, 3, 7, 1, 2, 6, 1, 1, 8, 2, 1, 2, 5, 2, 1, 2, 2, 1, 6, 1, 8, 1, 3, 10, 2, 4, 2, 1, 3, 4, 11, 6, 1, 2, 3, 4, 1, 1, 2, 7, 2, 2, 1, 1, 2, 13, 2, 5, 1, 6, 4, 1, 2, 8, 1, 1, 1, 1, 2, 1, 12, 1, 2, 2, 15, 1, 1, 4, 6, 4, 2, 2, 10, 6, 1, 3, 2, 1, 2, 3, 2

Offset: 1

Author

Reinhard Zumkeller, May 24 2009

Keywords

• nonn

Comments

A160697 and A160698 give record values and where they occur.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000188, A008864, A049097, A049098.

Programs

PARI

a(n) = core(prime(n)+1, 1)[2]; \\ Michel Marcus, Nov 06 2022

Formula

a(A049097(n)) = 1; a(A049098(n)) > 1;

a(n) = A000188(A008864(n)).