A249052 Odd numbers n without prime factors of the form 4k+3 such that x^2-n*y^2=-1 has no solutions.

205, 221, 305, 377, 505, 545, 689, 725, 745, 793, 905, 1205, 1345, 1405, 1469, 1513, 1517, 1537, 1717, 1885, 1945, 1961, 2005, 2041, 2045, 2105, 2225, 2245, 2329, 2353, 2525, 2533, 2669, 2701, 2845, 2993, 3005, 3205, 3305, 3497, 3505, 3737, 3757, 3805, 3893, 3965, 4069, 4105, 4145, 4205, 4321, 4369

Offset: 1

Author

Joerg Arndt, Apr 09 2008

Keywords

• nonn

Comments

A positive odd integer n is in this sequence iff its squarefree core A007913(n) belongs to A031398. - Max Alekseyev, Jun 26 2022

Crossrefs

Odd terms of A172001.

Cf. A031398, A031399, A137351.