A022332 Exponent of 2 (value of i) in n-th number of form 2^i*5^j.

0, 1, 2, 0, 3, 1, 4, 2, 0, 5, 3, 1, 6, 4, 2, 0, 7, 5, 3, 1, 8, 6, 4, 2, 9, 0, 7, 5, 3, 10, 1, 8, 6, 4, 11, 2, 9, 0, 7, 5, 12, 3, 10, 1, 8, 6, 13, 4, 11, 2, 9, 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9, 16, 0, 7, 14, 5, 12, 3, 10, 17, 1, 8, 15, 6, 13, 4, 11, 18, 2, 9, 16, 0, 7, 14, 5, 12, 19, 3, 10

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Links

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

Crossrefs

Cf. A003592, A007814, A022333.

Programs

Maple

A022332 := proc(n)
    A007814(A003592(n)) ;
end proc:
seq(A022332(n),n=1..20) ; # R. J. Mathar, Aug 04 2016

Mathematica

s = {}; m = 12; Do[n = 5^k; While[n <= 5^m, AppendTo[s, n]; n *= 2], {k, 0, m}]; IntegerExponent[#, 2] & /@ Union[s]

PARI

lista(nn) = {vec = vector(nn, i , i); subset = select(n->(n/(2^valuation(n,2)*5^valuation(n,5)) == 1), vec); for (i = 1, #subset, print1(valuation(subset[i], 2), ", "););} \\ Michel Marcus, Oct 01 2013

Formula

a(n) = A007814(A003592(n)). - Amiram Eldar, Feb 07 2020

Extensions

Corrected by David W. Wilson, Oct 15 1997