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A118016 Integers of the form 2^n/(n-1). 0
4, 4, 8, 64, 8192, 268435456, 576460752303423488, 5316911983139663491615228241121378304, 904625697166532776746648320380374280103671755200316906558262375061821325312 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..10.

FORMULA

a(n) = 4*A016031(n). - Paolo P. Lava, Nov 10 2006

EXAMPLE

n=5: 2^5/(5-1) = 32/4 = 8.

n=17: 2^17/(17-1) = 131072/16 = 8192.

MAPLE

P:=proc(n) local i, j; for i from 2 by 1 to n do j:=2^i/(i-1); if trunc(j)=j then print(j); fi; od; end: P(5000);

MATHEMATICA

f[n_]:=2^n/n*2; Select[Table[f[n], {n, 4, 6!}], IntegerQ] (* Vladimir Joseph Stephan Orlovsky, Dec 05 2009 *)

CROSSREFS

Cf. A016031 (De Bruijn's sequence: 2^(2^(n-1) - n)).

Sequence in context: A298569 A281717 A205971 * A201989 A071775 A269594

Adjacent sequences:  A118013 A118014 A118015 * A118017 A118018 A118019

KEYWORD

nonn

AUTHOR

Paolo P. Lava and Giorgio Balzarotti, May 11 2006

STATUS

approved

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Last modified April 6 11:51 EDT 2020. Contains 333273 sequences. (Running on oeis4.)