A104051 Integers where 3^n and 5^m are nearly the same gives a difference sequence.

3, 7, 399, 759, 971, 52947, 133663, 144027, 7011591, 18280739, 24294831, 926780523, 2486418967, 3842160243, 122290016319, 336572174651, 583349245479, 16110885760707, 45370056714703, 86112795218187, 2119413836354871

Offset

1,1

Comments

Sequence appears trisected: a(3m+3) = 2^(7m+3)-5^(3m+1), m>0; a(3m+1) = 2^(7m+5)-5^(3m+2), m>1; a(3m+2) = 2^(7m+7)-5^(3m+3), m>1. -- Ralf Stephan, Nov 13 2010.

Links

Table of n, a(n) for n=1..21.

Formula

a(q) = if 3^n>5^m and Floor[3^n/5^m]<2 then a[q]=Abs[3^n-5^m]

Mathematica

c = Delete[Union[Flatten[Table[Table[If [ (2^n > 5^m) && Floor[2^n/5^m] < 2, Abs[2^n - 5^m], 0], {m, 1, n}], {n, 1, 200}], 1]], 1]

Crossrefs

Sequence in context: A089689 A248701 A103317 * A128004 A281889 A086559

Adjacent sequences: A104048 A104049 A104050 * A104052 A104053 A104054

Keyword

nonn,uned

Author

Roger L. Bagula, Mar 01 2005

Status

approved