A175115 An integer k, k >=3, is included if d(k) = d(k-1)*d(k-2), where d(k) is the number of divisors of k.

3, 24, 120, 150, 195, 216, 294, 312, 399, 440, 459, 525, 540, 558, 570, 615, 630, 663, 693, 696, 744, 759, 774, 858, 999, 1032, 1095, 1125, 1152, 1176, 1239, 1350, 1455, 1470, 1494, 1608, 1624, 1659, 1664, 1710, 1725, 1734, 1785, 1860, 1880, 1896, 1914

Offset: 1

Author

Leroy Quet, Feb 13 2010

Keywords

• nonn

Comments

Terms calculated by M. F. Hasler.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A175116, A145469.

Programs

Mathematica

Transpose[Select[Partition[Range[2000], 3, 1], DivisorSigma[0, Last[#]] == DivisorSigma[0, First[#]] * DivisorSigma[0, #[[2]]]&]][[1]] + 2 (* Amiram Eldar, Jul 17 2019 after Harvey P. Dale at A175116 *)