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A082894 a(n) is the closest number to 2^n which is divisible by n. 8
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 18 20:10 EDT 2018. Contains 316325 sequences. (Running on oeis4.)