1,1

Table of n, a(n) for n=1..4.

E.g. a(2) = 3*3 = 9: divisors of 9 are 1, 3, 9, all of which are lucky numbers.

Cf. A057600, A000959.

Sequence in context: A144525 A276535 A228776 * A046239 A093351 A018543

Adjacent sequences: A087670 A087671 A087672 * A087674 A087675 A087676

nonn

Vit Planocka (planocka(AT)mistral.cz), Sep 26 2003

approved