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 A187261 #9 Mar 30 2012 17:31:31
%S A187261 1,2,14,19,211,463,634,1057,1951,2326,4156,5149,8254,9811,10651,21319,
%T A187261 15814,19609,29527,42379,46006,58171,89959,97579,144271,135319,164431,
%U A187261 217519,201919,230101,216451,285814,307759,323359
%N A187261 Least number k such that the continued fraction expansion of its square root contains the first n natural numbers.
%H A187261 Robert G. Wilson v, <a href="/A187261/b187261.txt">Table of n, a(n) for n = 1..100</a>
%e A187261 a(1) is 1.
%e A187261 a(2) is 2 because the cf of sqrt(2) = 1, 2, 2, .., .
%e A187261 a(3) is 14 because the cf of sqrt(14) = 3, {1, 2, 1, 6},
%e A187261 a(4) is 19 because the cf of sqrt(19) = 4, {2, 1, 3, 1, 2, 8},
%e A187261 a(5) is 211 because the cf of sqrt(211) = 14, {1, 1, 9, 5, 1, 2, 2, 1, 1, 4, 3, 1, 13, 1, 3, 4, 1, 1, 2, 2, 1, 5, 9, 1, 1, 28} which includes the natural numbers 1 through 5 and there does not exist any integer less than 211 which has this characteristics, etc.
%t A187261 f[n_] := Block[{cf = Union@ Flatten@ ContinuedFraction@ Sqrt@ n, k = 1}, While[k <= Length[cf] && k == cf[[k]], k++]; k - 1]; t = Table[ 0, {100}]; k = 1; While[k < 10^7, a = f@ k; If[a <= Length[t] && t[[a]] == 0, t[[a]] = k; Print[{a, k}]]; k++]; t
%Y A187261 Cf. A000027, A187142.
%K A187261 nonn
%O A187261 1,2
%A A187261 _Robert G. Wilson v_, Mar 07 2011