A140130 a(n) = denominator(c(n)) where c(n) = 1 if n=1, otherwise if n < 3*2^floor(log_2(n)-1) then c(n) = (c(floor(n/2))+c(floor((n+1)/2)))/2 otherwise c(n) = c(n-2^floor(log_2(n)))+1.

1, 1, 1, 1, 2, 1, 1, 1, 4, 2, 4, 1, 2, 1, 1, 1, 8, 4, 8, 2, 8, 4, 8, 1, 4, 2, 4, 1, 2, 1, 1, 1, 16, 8, 16, 4, 16, 8, 16, 2, 16, 8, 16, 4, 16, 8, 16, 1, 8, 4, 8, 2, 8, 4, 8, 1, 4, 2, 4, 1, 2, 1, 1, 1, 32, 16, 32, 8, 32, 16, 32, 4, 32, 16, 32, 8, 32, 16, 32, 2, 32, 16, 32, 8, 32, 16, 32, 4, 32, 16

Offset: 1

Author

Reinhard Zumkeller, May 14 2008

Keywords

• nonn
• frac

Comments

See A140129 for further comments and examples.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..8191

Crossrefs

Cf. A140129 (numerators).

Formula

a(n) = if n=1 then 1 else if n < 3*2^floor(log_2(n)-1) then (if n mod 2 = 0 then a(n/2) else 2^floor(log_2(n)-1)) else a(n-floor(log_2(n))).

For n>1: a(A023758(n)) = 1.