A161788 a(n) is the largest integer of the form 2^k - 1 that divides n.

1, 1, 3, 1, 1, 3, 7, 1, 3, 1, 1, 3, 1, 7, 15, 1, 1, 3, 1, 1, 7, 1, 1, 3, 1, 1, 3, 7, 1, 15, 31, 1, 3, 1, 7, 3, 1, 1, 3, 1, 1, 7, 1, 1, 15, 1, 1, 3, 7, 1, 3, 1, 1, 3, 1, 7, 3, 1, 1, 15, 1, 31, 63, 1, 1, 3, 1, 1, 3, 7, 1, 3, 1, 1, 15, 1, 7, 3, 1, 1, 3, 1, 1, 7, 1, 1, 3, 1, 1, 15, 7, 1, 31, 1, 1, 3, 1, 7, 3, 1, 1

Offset

1,3

Comments

a(n) = 2^A161789(n) - 1.

a(A161790(n)) = 1.

Links

Table of n, a(n) for n=1..101.

Maple

A161788 := proc(n) for k from ilog2(n+1) to 0 by -1 do if n mod (2^k-1) = 0 then RETURN(2^k-1); fi; od: end: seq(A161788(n), n=1..120) ; # R. J. Mathar, Jun 27 2009

Crossrefs

Cf. A000225, A161789, A161790.

Sequence in context: A363340 A058735 A107294 * A345468 A351518 A170819

Adjacent sequences: A161785 A161786 A161787 * A161789 A161790 A161791

Keyword

nonn

Author

Leroy Quet, Jun 19 2009

Extensions

Extended by R. J. Mathar, Jun 27 2009

Status

approved