A279537 Numbers of the form 2^i * 6^j * 30^k.

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

Offset: 1

Author

Charles R Greathouse IV, Dec 14 2016

Keywords

• nonn

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Crossrefs

Intersection of A025487 and A051037.

Cf. A025610.

Programs

Mathematica

mx = 6000; Take[ Sort[ Flatten[ Table[2^i*6^j*30^k, {i, 0, Log[2, mx]}, {j, 0, Log[6, mx]}, {k, 0, Log[30, mx]}]]], 60] (* Robert G. Wilson v, Dec 14 2016 *)

PARI

list(lim)=my(v=List(),x,y); for(k=0,logint(lim\=1,30), y=30^k; for(j=0,logint(lim\y,6), x=y*6^j; while(x<=lim, listput(v,x); x<<=1))); Set(v)

Formula

Sum_{n>=1} 1/a(n) = 72/29. - Amiram Eldar, Feb 18 2021