A010339 Numbers k such that the continued fraction for sqrt(k) has period 9.

106, 113, 137, 149, 265, 389, 493, 610, 698, 754, 970, 1037, 1258, 1418, 1450, 1586, 1618, 1781, 1882, 1949, 2554, 2570, 2725, 3074, 3869, 4082, 4505, 4825, 5090, 5213, 5309, 5722, 6266, 6305, 6530, 6749, 6757, 6994, 7013, 7178, 7202, 7538, 7873, 8501, 8545, 8882

Offset: 1

Author

N. J. A. Sloane and Walter Gilbert

Keywords

• nonn

Links

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

Programs

Mathematica

q[k_] := Module[{c = ContinuedFraction[Sqrt[k]]}, Length[c] == 2 && Length[c[[2]]] == 9]; Select[Range[10000], q] (* Amiram Eldar, Aug 21 2025 *)