A112760 - OEIS

A112760

Exponent of 2 (value of i) in n-th number of the form 2^i*3^j*5^k.

0, 1, 0, 2, 0, 1, 3, 0, 1, 2, 0, 4, 1, 2, 3, 0, 0, 1, 5, 2, 3, 0, 4, 1, 1, 2, 6, 3, 0, 4, 0, 1, 5, 2, 2, 3, 0, 7, 0, 4, 1, 5, 1, 2, 6, 3, 3, 0, 4, 0, 1, 8, 1, 5, 2, 6, 2, 3, 0, 7, 4, 0, 4, 1, 5, 1, 2, 9, 2, 6, 3, 0, 7, 3, 0, 4, 0, 1, 8, 5, 1, 5, 2, 6, 2, 3, 10, 3, 0, 7, 4, 0, 1, 8, 4, 1, 5, 1, 2, 9, 6, 2, 6, 3, 0

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OFFSET

1,4

LINKS

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

FORMULA

a(n) = A007814(A051037(n));

a(n) = A112759(n) - A112761(n) - A112762(n).

MATHEMATICA

IntegerExponent[#, 2] & /@ Select[Range[3000], Last @ Map[First, FactorInteger[#]] <= 5 &] (* Amiram Eldar, Feb 07 2020 *)

CROSSREFS

Cf. A007814, A022328, A051037, A112759, A112761, A112762.