A333964 Numbers of the form 2^i * 6^j * 30^k * 210^m where i, j, k, m >= 0.

1, 2, 4, 6, 8, 12, 16, 24, 30, 32, 36, 48, 60, 64, 72, 96, 120, 128, 144, 180, 192, 210, 216, 240, 256, 288, 360, 384, 420, 432, 480, 512, 576, 720, 768, 840, 864, 900, 960, 1024, 1080, 1152, 1260, 1296, 1440, 1536, 1680, 1728, 1800, 1920, 2048, 2160, 2304, 2520, 2592

Offset: 1

Author

David A. Corneth, Apr 20 2020

Keywords

• nonn

Links

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

Crossrefs

Intersection of A025487 and A002473.

Cf. A025610, A279537.

Programs

Mathematica

mx = 2600; Select[Sort[Flatten[Table[2^i*6^j*30^k*210^m, {i, 0, Log[2, mx]}, {j, 0, Log[6, mx]}, {k, 0, Log[30, mx]}, {m, 0, Log[210, mx]}]]], # <= mx &] (* Amiram Eldar, Apr 24 2020 after Robert G. Wilson v at A279537 *)

Formula

Sum_{n>=1} 1/a(n) = 15120/6061. - Amiram Eldar, Feb 18 2021