login
A031600
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 12.
0
1049, 3217, 3445, 5021, 6569, 8506, 8689, 11314, 11738, 11953, 14285, 16825, 17341, 18397, 20129, 20693, 21554, 22138, 22433, 22826, 23729, 24034, 24341, 24961, 25274, 25589, 26546, 29629, 30313, 31817, 33965, 35437, 35930, 36682, 37061, 38210
OFFSET
1,1
EXAMPLE
CF(sqrt(145)) = (12, (24)), therefore 145 is not in the sequence.
CF(sqrt(1049)) = (32, (2,1,1,2,1,4,3,1,5,7,1,12, 12,1,7,5,1,3,4,1,2,1,1,2, 64)), therefore 1049 is in the sequence.
CROSSREFS
Sequence in context: A337960 A331346 A164771 * A251272 A030083 A184203
KEYWORD
nonn
EXTENSIONS
First term 145 removed by Georg Fischer, Jun 15 2019
Definition clarified by N. J. A. Sloane, Aug 18 2021
STATUS
approved