A077198 a(n) = lambda(sigma(n)), where lambda(n) is the Carmichael lambda function, which gives the smallest integer m such that k^m = 1 mod n for all integers k relatively prime to n.

1, 2, 2, 6, 2, 2, 2, 4, 12, 6, 2, 6, 6, 2, 2, 30, 6, 12, 4, 6, 8, 6, 2, 4, 30, 6, 4, 6, 4, 6, 8, 6, 4, 18, 4, 12, 18, 4, 6, 12, 6, 8, 10, 6, 12, 6, 4, 30, 18, 30, 6, 42, 18, 4, 6, 4, 4, 12, 4, 6, 30, 8, 12, 126, 6, 12, 16, 6, 8, 12, 6, 12, 36, 18, 30, 12, 8, 6, 4, 30, 110, 6, 6, 24, 18, 10, 4

Offset: 1

Author

Joseph L. Pe, Nov 30 2002

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384
• Index entries for sequences related to sigma(n)

Crossrefs

Cf. A000203, A002322.

Cf. also A062401, A290088.

Programs

Mathematica

Table[CarmichaelLambda[DivisorSigma[1, n]], {n, 1, 100}]

PARI

A077198(n) = lcm(znstar(sigma(n))[2]); \\ Antti Karttunen, Nov 18 2017

Formula

a(n) = A002322(A000203(n)). - Antti Karttunen, Nov 18 2017