A085125 Even numbers which are 7-smooth.

2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 48, 50, 54, 56, 60, 64, 70, 72, 80, 84, 90, 96, 98, 100, 108, 112, 120, 126, 128, 140, 144, 150, 160, 162, 168, 180, 192, 196, 200, 210, 216, 224, 240, 250, 252, 256, 270, 280, 288, 294, 300, 320, 324, 336

Offset

1,1

Comments

Equivalently, multiples of 2 with the largest prime divisor < 10.

Links

Table of n, a(n) for n=1..61.

Formula

From Amiram Eldar, Sep 23 2024: (Start)

a(n) = 2*A002473(n).

Sum_{n>=1} 1/a(n) = 35/16. (End)

Mathematica

Select[2*Range[200], FactorInteger[#][[-1, 1]]<10&] (* Harvey P. Dale, Jul 06 2018 *)

Crossrefs

Intersection of A005843 and A002473.

Cf. A085126, A085127, A085128, A085129, A080194, A085131, A085132.

Sequence in context: A221284 A272670 A234521 * A251237 A194402 A134930

Adjacent sequences: A085122 A085123 A085124 * A085126 A085127 A085128

Keyword

nonn,easy

Author

Amarnath Murthy, Jul 06 2003

Extensions

More terms from David Wasserman, Jan 28 2005

Offset changed by Andrew Howroyd, Sep 19 2024

Status

approved