A238162 Least common multiple of the prime factors of n, each increased by 1.

3, 4, 3, 6, 12, 8, 3, 4, 6, 12, 12, 14, 24, 12, 3, 18, 12, 20, 6, 8, 12, 24, 12, 6, 42, 4, 24, 30, 12, 32, 3, 12, 18, 24, 12, 38, 60, 28, 6, 42, 24, 44, 12, 12, 24, 48, 12, 8, 6, 36, 42, 54, 12, 12, 24, 20, 30, 60, 12, 62, 96, 8, 3, 42, 12, 68, 18, 24, 24, 72, 12, 74, 114, 12, 60, 24, 84, 80, 6, 4, 42, 84, 24, 18, 132, 60, 12, 90, 12, 56, 24, 32, 48, 60, 12, 98, 24, 12, 6

Offset

2,1

Comments

If n is prime, then a(n) = n + 1. - Wesley Ivan Hurt, Apr 05 2014

If n is a composite squarefree number and a(n) divides n+1, then n is a Lucas-Carmichael number (A006972). - Daniel Suteu, Oct 02 2022

Links

Daniel Suteu, Table of n, a(n) for n = 2..10000

Example

The prime factors of 6 are 2 and 3, which become 3 and 4 when respectively increased by 1, and lcm(3, 4) = 12. Therefore, a(6) = 12.

Prog

(PARI) a(n) = my(f=factor(n)); lcm(vector(#f~, k, f[k, 1]+1)); \\ Daniel Suteu, Oct 02 2022

Crossrefs

Cf. A006972.

Sequence in context: A061800 A218789 A324335 * A367503 A048250 A323363

Adjacent sequences: A238159 A238160 A238161 * A238163 A238164 A238165

Keyword

nonn

Author

Joseph L. Pe, Feb 18 2014

Status

approved