A022336 Exponent of 3 (value of i) in n-th number of form 3^i*5^j.

0, 1, 0, 2, 1, 0, 3, 2, 1, 4, 0, 3, 2, 5, 1, 4, 0, 3, 6, 2, 5, 1, 4, 7, 0, 3, 6, 2, 5, 8, 1, 4, 7, 0, 3, 6, 9, 2, 5, 8, 1, 4, 7, 10, 0, 3, 6, 9, 2, 5, 8, 11, 1, 4, 7, 10, 0, 3, 6, 9, 12, 2, 5, 8, 11, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 2, 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2, 5, 8, 11, 14, 1, 4, 7

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Links

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

Crossrefs

Cf. A003593, A007949, A022329, A022337, A112754, A112761.

Programs

Mathematica

s = {}; m = 12; Do[n = 5^k; While[n <= 5^m, AppendTo[s, n]; n *= 3], {k, 0, m}]; IntegerExponent[#, 3] & /@ Union[s] (* Amiram Eldar, Feb 06 2020 *)

Formula

a(n) = A007949(A003593(n)) = A112754(n) - A022337(n). - Reinhard Zumkeller, Sep 18 2005