A134614 Numbers (excluding primes and powers of primes) such that the root mean cube of their prime factors is an integer (where the root mean cube of c and d is ((c^3+d^3)/2)^(1/3)).

1512, 337365, 375360, 523809, 707265, 1177176, 1255254, 1380918, 1549431, 1922816, 2277345, 2284389, 2286144, 2816883, 3320713, 3340428, 3838185, 4378333, 6726969, 7043655, 8311212, 10281284, 10323390, 10666227, 10708544

Offset: 1

Author

Hieronymus Fischer, Nov 11 2007

Keywords

• nonn

Comments

The prime factors are taken with multiplicity.

Numbers included in A134611, but not in A025475.

a(1) = 1512 is the minimal number with this property.

Examples

			a(1) = 1512, since 1512 = 2*2*2*3*3*3*7 and ((2^3+2^3+2^3+3^3+3^3+3^3+7^3)/7)^(1/3) = 64^(1/3) = 4.
		

Links

• Hieronymus Fischer, Table of n, a(n) for n = 1..520

Crossrefs

Cf. A001597, A025475, A134333, A134344, A134376.

Cf. A134600, A134602, A134605, A134608, A134611, A134619, A134621.

Extensions

Minor edits and more terms added by Hieronymus Fischer, May 06 2013, May 30 2013