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Revision History for A031416

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Showing entries 1-10 | older changes
Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 3.
(history; published version)
#20 by N. J. A. Sloane at Wed Aug 18 00:33:16 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 then there are a pair of central terms both equal to 3.

Discussion
Wed Aug 18
00:33
OEIS Server: https://oeis.org/edit/global/2909
#19 by Joerg Arndt at Sun Jul 11 09:47:59 EDT 2021
STATUS

proposed

approved

#18 by Michel Marcus at Sun Jul 11 08:53:14 EDT 2021
STATUS

editing

proposed

#17 by Michel Marcus at Sun Jul 11 08:53:10 EDT 2021
CROSSREFS

Subsequence of A003814.

STATUS

proposed

editing

#16 by Jon E. Schoenfield at Sun Jul 11 08:48:42 EDT 2021
STATUS

editing

proposed

#15 by Jon E. Schoenfield at Sun Jul 11 08:48:40 EDT 2021
NAME

Numbers n k such that the continued fraction for sqrt(nk) has odd period and a pair of central terms both equal to 3.

STATUS

approved

editing

#14 by Harvey P. Dale at Wed Sep 25 20:26:01 EDT 2019
STATUS

editing

approved

#13 by Harvey P. Dale at Wed Sep 25 20:25:57 EDT 2019
MATHEMATICA

cfo3Q[n_]:=Module[{s=Sqrt[n], cf, len}, cf=If[IntegerQ[s], {0, 0}, ContinuedFraction[ s ][[2]]]; len=Length[cf]; OddQ[len]&&cf[[ (len+1)/2]] == cf[[(len-1)/2]]==3]; Select[Range[3300], cfo3Q] (* Harvey P. Dale, Sep 25 2019 *)

STATUS

approved

editing

#12 by Michael Somos at Sun Apr 20 21:57:41 EDT 2014
STATUS

editing

approved

#11 by Michael Somos at Sun Apr 20 21:57:21 EDT 2014
NAME

Numbers n such that continued fraction for sqrt(n) has odd period and a pair of central term terms both equal to 3.

STATUS

approved

editing

Discussion
Sun Apr 20
21:57
Michael Somos: See A031415 for NAME change.