A279635 Denominator of (0 followed by A005126(n)= 2, 4, 7, ...)/2^n, a sequence corresponding to A271573.

1, 1, 1, 8, 4, 32, 32, 128, 32, 512, 512, 2048, 1024, 8192, 8192, 32768, 4096, 131072, 131072, 524288, 262144, 2097152, 2097152, 8388608, 2097152, 33554432, 33554432, 134217728, 67108864, 536870912, 536870912, 2147483648, 134217728, 8589934592, 8589934592, 34359738368, 17179869184, 137438953472, 137438953472, 549755813888, 137438953472

Offset: 0

Author

Jean-François Alcover and Paul Curtz, Dec 16 2016

Keywords

• nonn
• frac

Crossrefs

Cf. A005126, A075101, A271573.

Programs

Mathematica

a[0] = 1; a[n_] := Denominator[(2^(n-1)+n)/2^n]; Table[a[n], {n, 0, 40}]
(* or *)
a[0] = 1; a[n_] := 2^(n-IntegerExponent[2^(n-1)+n, 2]); Table[a[n], {n, 0, 40}]

Formula

a(n) = 2^(n-valuation(2^(n-1)+n,2)), with a(0) = 1.