A125035 Numbers k such that gcd(2^k-69,k) > 1.

10, 26, 30, 50, 67, 70, 88, 90, 110, 130, 136, 150, 170, 182, 183, 185, 190, 198, 210, 212, 230, 250, 270, 272, 285, 290, 308, 310, 330, 338, 350, 370, 390, 408, 410, 413, 418, 430, 450, 470, 490, 494, 510, 528, 530, 544, 550, 570, 590, 610, 627, 630, 638, 650

Offset

1,1

Comments

The corresponding gcd's are 5,13,5,5,67,5,11,5,5,5,17,5,5,13,61,37,5,11, ...

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

10 is a term since gcd(2^10-69,10) = gcd(1024-69,10) = gcd(955,10) = 5 > 1.
Note that 67|(2^67-69).

Mathematica

Select[Range[650], ! CoprimeQ[2^# - 69, #] &] (* Amiram Eldar, Feb 18 2022 *)

Crossrefs

Cf. A124977, A125034.

Sequence in context: A358774 A046961 A246826 * A337049 A067264 A043342

Adjacent sequences: A125032 A125033 A125034 * A125036 A125037 A125038

Keyword

nonn

Author

Zak Seidov, Nov 17 2006

Extensions

More terms from Amiram Eldar, Feb 18 2022

Status

approved