A306667 - OEIS

A306667

Numbers m such that lcm(tau(m), m) = sigma(m) where sigma(k) = the sum of the divisors of k (A000203) and tau(k) = the number of the divisors of k (A000005).

1, 6, 32760, 51001180160, 54530444405217553992377326508106948362108928, 133821156044600922812153118065015159487725568, 42274041475824304453686528060845522019324411248640, 48949643430560436794021629524876790263031553747866371344635527168

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OFFSET

1,2

COMMENTS

Numbers m such that A009230(m) = A000203(m).

Subsequence of multiply-perfect numbers (A007691).

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..11 (from A007691 data)

EXAMPLE

6 is a term because lcm(tau(6), 6) = lcm(4, 6) = 12 = sigma(6).

PROG

(Magma) [n: n in [1..100000] | LCM(NumberOfDivisors(n), n) eq SumOfDivisors(n)]