A084200 LeastCommonMultiple{q+1: q prime, q < prime(n), q+1 divides prime(n)+1}.

1, 1, 3, 4, 12, 1, 6, 4, 24, 6, 8, 1, 42, 4, 24, 18, 60, 1, 4, 72, 1, 40, 84, 90, 14, 6, 8, 108, 1, 114, 32, 132, 6, 140, 30, 152, 1, 4, 168, 6, 180, 14, 96, 1, 18, 40, 4, 224, 228, 1, 18, 240, 1, 252, 6, 264, 270, 136, 1, 6, 4, 294, 308, 312, 1, 6, 4, 1, 348, 14, 6, 360, 8, 1

Offset: 1

Author

Reinhard Zumkeller, May 18 2003

Keywords

• nonn

Links

• Matthew House, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A084196, A082539, A084197.

Programs

Python

from math import lcm
from sympy import sieve
def a(n):
    pn = sieve[n]
    return lcm(*[q+1 for q in sieve.primerange(2, pn) if (pn+1)%(q+1)==0])
print([a(n) for n in range(1, 100)]) # Michael S. Branicky, Aug 13 2024

Extensions

Definition and terms corrected by Matthew House, Aug 13 2024