This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A146329 #22 May 01 2021 06:48:21
%S A146329 6,7,8,14,20,23,24,28,32,33,34,42,47,48,52,55,60,62,69,72,75,78,79,80,
%T A146329 95,98,110,119,120,126,133,135,136,138,140,141,142,156,167,168,174,
%U A146329 180,189,194,205,210,213,215,219,220,222,223,224,248,252,254,272,287,288
%N A146329 Numbers k such that continued fraction of (1 + sqrt(k))/2 has period 4.
%C A146329 For primes in this sequence see A028871 - {2}.
%H A146329 Amiram Eldar, <a href="/A146329/b146329.txt">Table of n, a(n) for n = 1..10000</a>
%e A146329 a(2) = 7 because continued fraction of (1 + sqrt(7))/2 = 1, 1, 4, 1, 1, 1, 4, 1, 1, 1, 4, ... has period (1,1,4,1) length 4.
%p A146329 isA146329 := proc(n) RETURN(A146326(n) = 4) ; end:
%p A146329 for n from 2 to 400 do if isA146329(n) then printf("%d,",n) ; fi; od: # _R. J. Mathar_, Sep 06 2009
%t A146329 cf4Q[n_]:=Module[{s=(1+Sqrt[n])/2},If[IntegerQ[s],1,Length[ ContinuedFraction[ s][[2]]]]==4]; Select[Range[300],cf4Q] (* _Harvey P. Dale_, Dec 14 2017 *)
%Y A146329 Cf. A000290, A078370, A146326-A146345, A028871, A146348-A146360.
%K A146329 nonn
%O A146329 1,1
%A A146329 _Artur Jasinski_, Oct 30 2008
%E A146329 39, 68, 150, 155, etc. removed by _R. J. Mathar_, Sep 06 2009