A109138 - OEIS

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A109138

Numbers n such that 2^n + 2 is an admirable number (A111592).

6, 8, 12, 14, 18, 20, 24, 32, 44, 62, 80, 102, 128, 168, 192, 200, 314, 348, 702

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

For k > 1, A000978(k)+1 is a member. Are there any others? - David Wasserman, May 28 2008

No more terms below 1064. - Amiram Eldar, Oct 12 2019

LINKS

Table of n, a(n) for n=1..19.

EXAMPLE

a(3)=12 because 2^12 + 2 = 4098 and 1+2+3+683+1366+2049-6 = 4098.

MATHEMATICA

fQ[n_] := Block[{d = Most[ Divisors[n]], k = 1}, l = Length[d]; s = Plus @@ d; While[k < l && s - 2d[[k]] > n, k++ ]; If[k > l || s != n + 2d[[k]], False, True]]; Do[ If[ fQ[2^n + 2], Print[n]], {n, 200}] (* Robert G. Wilson v, Aug 30 2005 *)

CROSSREFS

Cf. A000978.

Sequence in context: A242058 A322293 A366442 * A315858 A123303 A063207

Adjacent sequences: A109135 A109136 A109137 * A109139 A109140 A109141

KEYWORD

nonn,more

AUTHOR

Jason Earls, Aug 18 2005

EXTENSIONS

More terms from David Wasserman, May 28 2008

a(19) from Amiram Eldar, Oct 12 2019

STATUS

approved