A031519 Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 21.

443, 451, 459, 463, 467, 479, 487, 491, 499, 503, 511, 523, 527, 1768, 1832, 1856, 1888, 1920, 1952, 2048, 2080, 2112, 3975, 4035, 4119, 4191, 4395, 4479, 4611, 4695, 4755, 7064, 7128, 7256, 7432, 7512, 7576, 7688, 7704, 7768, 7816, 8072, 8152, 8408, 8456

Offset

1,1

Links

Table of n, a(n) for n=1..45.

Crossrefs

Sequence in context: A225350 A171392 A105980 * A360827 A031699 A158321

Adjacent sequences: A031516 A031517 A031518 * A031520 A031521 A031522

Keyword

nonn

Author

David W. Wilson

Status

approved