A085129 Multiples of 6 which are 7-smooth.

6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 72, 84, 90, 96, 108, 120, 126, 144, 150, 162, 168, 180, 192, 210, 216, 240, 252, 270, 288, 294, 300, 324, 336, 360, 378, 384, 420, 432, 450, 480, 486, 504, 540, 576, 588, 600, 630, 648, 672, 720, 750, 756, 768, 810, 840

Offset: 1

Author

Amarnath Murthy, Jul 06 2003

Keywords

• nonn
• easy

Comments

Equivalently, multiples of 6 with the largest prime divisor < 10.

Crossrefs

Intersection of A008588 and A002473.

Cf. A085125, A085126, A085127, A085128, A080194, A085131, A085132.

Programs

Mathematica

With[{p = Prime[Range[4]]}, 6 * Select[Range[140], Times @@ (p^IntegerExponent[#, p]) == # &]] (* Amiram Eldar, Sep 23 2024 *)

Formula

From Amiram Eldar, Sep 22 2024: (Start)

a(n) = 6*A002473(n).

Sum_{n>=1} 1/a(n) = 35/48. (End)

Extensions

More terms from David Wasserman, Jan 28 2005

Offset changed by Andrew Howroyd, Sep 19 2024