A091448 Numbers k such that a1 > a2, where [a0,a1,a2,...] is the simple continued fraction of sqrt(k).

19, 28, 29, 52, 53, 54, 67, 70, 85, 86, 88, 103, 106, 107, 108, 124, 125, 126, 127, 129, 149, 151, 153, 172, 173, 174, 175, 176, 178, 179, 199, 201, 202, 204, 206, 207, 229, 232, 233, 234, 236, 237, 259, 261, 262, 263, 265, 267, 268, 292, 293, 294, 295, 296

Offset

1,1

Links

Table of n, a(n) for n=1..54.

Example

sqrt(19) = [4;2,1,3,1,2,8,...], for which a1 = 2 > 1 = a2.

Mathematica

Select[Range@300, Quiet[#[[1]]>#[[2]]&[Last@ContinuedFraction[Sqrt@#]]]&] (* Giorgos Kalogeropoulos, Jul 04 2021 *)

Prog

(PARI) for(k=2, 300, my(c=contfrac(sqrt(k))); if(#c>=3&&c[2]>c[3], print1(k, ", "))) \\ Hugo Pfoertner, Jul 04 2021

Crossrefs

Cf. A000196, A091453.

Sequence in context: A298638 A291884 A173639 * A067777 A065207 A084364

Adjacent sequences: A091445 A091446 A091447 * A091449 A091450 A091451

Keyword

nonn

Author

Clark Kimberling, Jan 10 2004

Status

approved