A346481 a(n) = A346467(n) / A346466(n) = lcm S / lcm {d in S, d+1 | n}, with S = {d | n-1, d+1 is prime}.

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 8, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 8, 1, 5, 1, 1, 1, 18, 1, 14, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 40, 1, 1, 1, 21, 1, 1, 1, 1, 1, 15, 1, 46, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 13

Offset: 1

Author

Antti Karttunen, Jul 31 2021

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..20000

Crossrefs

Cf. A346466, A346467.

Programs

PARI

A346481(n) = if(1==n,n,my(m1=1,m2=1); fordiv(n-1,d,if(isprime(1+d), m1 = lcm(m1,d); if(!(n%(1+d)), m2 = lcm(m2,d)))); (m1/m2));

Formula

a(n) = A346467(n) / A346466(n).