OFFSET
1,2
COMMENTS
1 together with numbers of the form 2^i * 3^j with i >= j >= 1. - Amiram Eldar, Jul 11 2023
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Smooth Number.
FORMULA
Sum_{n>=1} 1/a(n) = 7/5. - Amiram Eldar, Jul 11 2023
MATHEMATICA
With[{max = 70000}, Join[{1}, Sort[Flatten[Table[2^i*3^j, {i, 1, Log2[max]}, {j, 1, Min[i, Log[3, max/2^i]]}]]]]] (* Amiram Eldar, Jul 11 2023 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Nov 04 2006
EXTENSIONS
Missing term a(43) inserted and more terms added by Amiram Eldar, Jul 11 2023
STATUS
approved