A082894 a(n) is the closest number to 2^n which is divisible by n.

2, 4, 9, 16, 30, 66, 126, 256, 513, 1020, 2046, 4092, 8190, 16380, 32775, 65536, 131070, 262152, 524286, 1048580, 2097144, 4194300, 8388606, 16777224, 33554425, 67108860, 134217729, 268435468, 536870910, 1073741820, 2147483646

Offset

1,1

Links

G. C. Greubel, Table of n, a(n) for n = 1..1000

Formula

a(n) = n*floor( (floor(n/2)+2^n) / n ).

Example

n=11: 2^11=2048 is between 2046=11.186 and 2035=11.185, closer to a(11)=2046;
Powers of two are fixed points of this map.

Maple

A082894:=n->n*floor((floor(n/2)+2^n)/n); seq(A082894(k), k=1..100); # Wesley Ivan Hurt, Oct 29 2013

Mathematica

Table[n*Floor[(Floor[n/2]+2^n)/n], {n, 100}]

Prog

(PARI) for(n=1, 50, print1(n*floor( (floor(n/2)+2^n) / n ), ", ")) \\ G. C. Greubel, Aug 08 2017

Crossrefs

Cf. A082893, A082895, A082896, A082897, A082898, A082899, A082900.

Sequence in context: A174511 A034452 A034449 * A302831 A091437 A131337

Adjacent sequences: A082891 A082892 A082893 * A082895 A082896 A082897

Keyword

nonn

Author

Labos Elemer, Apr 22 2003

Status

approved