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 A272208 #24 May 21 2016 23:26:19 %S A272208 8,77,5711,9797,997997,8053139,60755907,99979997,9999799997, %T A272208 71515443427,93445113269,999997999997,26369408771424,96872443448748, %U A272208 99650905131203,99999979999997,751273714618266,3368237924952647,3493498117381256,9999999799999997,35399255736521405,999999997999999997 %N A272208 Numbers n such that n immediately follows the decimal point in the base-10 representation of sqrt(n). %C A272208 Sequence includes all numbers of form (10^n-3)(10^n+1) for n >= 1, hence is infinite. %H A272208 David W. Wilson, <a href="/A272208/b272208.txt">Table of n, a(n) for n = 1..27</a> %e A272208 5711 immediately follows the decimal in sqrt(5711) = 75.5711+, so 5711 is in the sequence. %e A272208 77327 does not immediately follow the decimal in sqrt(77327) = 278.077327+, so 77327 is not in this sequence. %o A272208 (PARI) is(n)=my(t=10^#Str(n)); sqrtint(t^2*n)%t==n \\ _Charles R Greathouse IV_, May 16 2016 %Y A272208 Strict subsequence of A074841. %K A272208 nonn,base,hard %O A272208 1,1 %A A272208 _David W. Wilson_, May 15 2016