A031609 - OEIS

%I #14 Aug 18 2021 00:10:32

%S 1033,5674,9106,9685,13577,14045,19213,19769,20333,25189,26794,33413,

%T 33778,40361,41165,42797,43625,51517,53341,59093,59578,61538,63029,

%U 64033,69269,70321,71381,71914,72986,74066,74609,75154,75701,93257,94477,96941

%N Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 21.

%Y Subsequence of A003814.

%K nonn

%O 1,1

%A _David W. Wilson_

%E First term 442 removed by _Georg Fischer_, Jun 16 2019