A031697 Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 19.

363, 1448, 3255, 5784, 9035, 13008, 17703, 23120, 29259, 36120, 43703, 52008, 61035, 70784, 81255, 92448, 104363, 117000, 130359, 137680, 144440, 152920, 159243, 174768, 191015, 207984, 225675, 244088, 263223, 283080, 303659, 314780, 324960

Offset

1,1

Comments

(19*m)^2 + 2*m for m >= 1 are terms of this sequence (see comment in A031749). The first term that is not of this form is a(20) = 137680. - Chai Wah Wu, Jun 19 2016

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 60 terms from Vincenzo Librandi)

Mathematica

Select[Range[350000], !IntegerQ[Sqrt[#]] &&Min[ContinuedFraction[Sqrt[#]][[2]]] == 19&](* Vincenzo Librandi, Feb 10 2012 *)

Crossrefs

Sequence in context: A031517 A192449 A116285 * A158309 A098251 A115464

Adjacent sequences: A031694 A031695 A031696 * A031698 A031699 A031700

Keyword

nonn

Author

David W. Wilson

Status

approved