A107764 Numbers of the form (8^i)*(13^j), with i, j >= 0.

1, 8, 13, 64, 104, 169, 512, 832, 1352, 2197, 4096, 6656, 10816, 17576, 28561, 32768, 53248, 86528, 140608, 228488, 262144, 371293, 425984, 692224, 1124864, 1827904, 2097152, 2970344, 3407872, 4826809, 5537792, 8998912, 14623232, 16777216

Offset: 1

Author

Douglas Winston (douglas.winston(AT)srupc.com), Jun 11 2005

Keywords

• nonn
• easy

Links

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

Crossrefs

Cf. A025633, A025634, A107326, A107364, A107462, A107466, A107710, A108056, A108090.

Programs

Mathematica

n = 10^6; Flatten[Table[8^i*13^j, {i, 0, Log[8, n]}, {j, 0, Log[13, n/8^i]}]] // Sort (* Amiram Eldar, Sep 25 2020 *)

Formula

Sum_{n>=1} 1/a(n) = (8*13)/((8-1)*(13-1)) = 26/21. - Amiram Eldar, Sep 25 2020

a(n) ~ exp(sqrt(2*log(8)*log(13)*n)) / sqrt(104). - Vaclav Kotesovec, Sep 25 2020