The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A031632 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A031632

Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 44.
(history; published version)

#16 by N. J. A. Sloane at Wed Aug 18 00:10:32 EDT 2021

NAME

Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 44.

Discussion

Wed Aug 18

00:10

OEIS Server: https://oeis.org/edit/global/2908

#15 by Jon E. Schoenfield at Sun Jul 11 07:55:51 EDT 2021

STATUS

editing

approved

#14 by Jon E. Schoenfield at Sun Jul 11 07:55:32 EDT 2021

NAME

Numbers k such that the continued fraction for sqrt(k) has odd period and central term terms 44.

STATUS

approved

editing

#13 by Hugo Pfoertner at Sun Jul 11 07:50:06 EDT 2021

STATUS

proposed

approved

#12 by Jon E. Schoenfield at Sun Jul 11 07:40:08 EDT 2021

STATUS

editing

proposed

#11 by Jon E. Schoenfield at Sun Jul 11 07:40:06 EDT 2021

NAME

Numbers n k such that the continued fraction for sqrt(nk) has odd period and central term 44.

STATUS

approved

editing

#10 by Harvey P. Dale at Sun May 10 12:15:58 EDT 2020

STATUS

editing

approved

#9 by Harvey P. Dale at Sun May 10 12:15:53 EDT 2020

NAME

Numbers n such that continued fraction for sqrt(n) has odd period and central terms term 44.

DATA

485, 12569, 24074, 24698, 60637, 83113, 84269, 111781, 140914, 146213, 180137, 181837, 215737, 217597, 223225, 260629, 262673, 304226, 305329, 306434, 307541, 310874, 311989, 315346, 316469, 363133, 415577, 418157, 420745, 423341, 425945

MATHEMATICA

cf44Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {1, 1}, ContinuedFraction[ s][[2]]]; len=Length[cf]; OddQ[len]&&cf[[(len+1)/2]] == 44]; Select[Range[426000], cf44Q] (* Harvey P. Dale, May 10 2020 *)

EXTENSIONS

First term (485) added and definition clarified by Harvey P. Dale, May 10 2020

STATUS

approved

editing

#8 by Georg Fischer at Sun Jun 16 03:29:18 EDT 2019

STATUS

editing

approved

#7 by Georg Fischer at Sun Jun 16 03:29:14 EDT 2019

DATA

1937, 12569, 24074, 24698, 60637, 83113, 84269, 111781, 140914, 146213, 180137, 181837, 215737, 217597, 223225, 260629, 262673, 304226, 305329, 306434, 307541, 310874, 311989, 315346, 316469, 363133, 415577, 418157, 420745, 423341, 425945

EXTENSIONS

First term 1937 removed by Georg Fischer, Jun 16 2019

STATUS

approved

editing