1,2

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

A000005(a(n)) = a(n-1) + 3 for n >= 2.

a(3) = 36 = the smallest number with 6 + 3 = 9 divisors.

Cf. A014221, A175718, A175720.

Sequence in context: A202781 A067213 A173604 * A277726 A003351 A129651

Adjacent sequences: A175716 A175717 A175718 * A175720 A175721 A175722

nonn

Jaroslav Krizek, Aug 15 2010

approved