A072695 - OEIS

A072695

a(n) = lcm(d(n^2),d(n)), where d(n) = A000005, the number of divisors of n.

1, 6, 6, 15, 6, 36, 6, 28, 15, 36, 6, 30, 6, 36, 36, 45, 6, 30, 6, 30, 36, 36, 6, 168, 15, 36, 28, 30, 6, 216, 6, 66, 36, 36, 36, 225, 6, 36, 36, 168, 6, 216, 6, 30, 30, 36, 6, 270, 15, 30, 36, 30, 6, 168, 36, 168, 36, 36, 6, 180, 6, 36, 30, 91, 36, 216, 6, 30, 36, 216, 6, 420

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..16384

Index entries for sequences computed from exponents in factorization of n.

Index entries for sequences related to LCM.

FORMULA

If n is squarefree product of k distinct primes, then a(n) = 6^k.

If n = p^2, then a(n) = 15, etc.

MATHEMATICA

Table[LCM[DivisorSigma[0, n], DivisorSigma[0, n^2]], {n, 80}] (* Harvey P. Dale, Dec 26 2018 *)