Numbers k such that the period of the continued fraction for sqrt(k) contains exactly three 1's.

Terms

a(0) =7a(1) =32a(2) =75a(3) =88a(4) =136a(5) =215a(6) =279a(7) =280a(8) =312a(9) =403a(10) =427a(11) =560a(12) =711a(13) =736a(14) =851a(15) =880a(16) =923a(17) =1007a(18) =1067a(19) =1272a(20) =1311a(21) =1363a(22) =1431a(23) =1495a(24) =1736a(25) =1855a(26) =1887a(27) =1955a(28) =1976a(29) =1995