A224499 - OEIS

%I #12 Oct 13 2020 05:45:31

%S 1,5,29,53,89,113,173,209,329,413,509,545,713,725,809,833,893,965,

%T 1013,1133,1169,1625,1649,1685,1733,1769,1925,2009,2045,2129,2273,

%U 2393,2465,2549,2825,2933,3065,3149,3329,3389,3413,3473,3605,3653,3665,3773

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

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

%H Amiram Eldar, <a href="/A224499/b224499.txt">Table of n, a(n) for n = 1..10000</a>

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

%Y Cf. A000051, A224486.

%K nonn

%O 1,2

%A _Jayanta Basu_, Apr 08 2013