A224499 Numbers k such that if 2*k+1 divides 2^k+1 then 2*(k+1)+1 divides 2^(k+1)+1.

1, 5, 29, 53, 89, 113, 173, 209, 329, 413, 509, 545, 713, 725, 809, 833, 893, 965, 1013, 1133, 1169, 1625, 1649, 1685, 1733, 1769, 1925, 2009, 2045, 2129, 2273, 2393, 2465, 2549, 2825, 2933, 3065, 3149, 3329, 3389, 3413, 3473, 3605, 3653, 3665, 3773

Offset: 1

Author

Jayanta Basu, Apr 08 2013

Keywords

• nonn

Comments

First of a pair of consecutive Curzon numbers, where Curzon numbers are given by A224486.

Links

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

Crossrefs

Cf. A000051, A224486.

Programs

Mathematica

CuQ[n_] := IntegerQ[(2^n + 1)/(2*n + 1)]; Select[Range[4000], CuQ[#] && CuQ[# + 1] &]