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 A067722 #14 Feb 07 2015 06:24:25
%S A067722 1,3,6,9,5,15,18,21,10,7,30,33,15,39,42,45,9,51,14,57,25,63,66,69,30,
%T A067722 11,78,21,35,87,90,93,18,99,102,105,13,111,114,117,50,123,126,129,55,
%U A067722 35,138,141,27,15,22,153,65,159,42,165,70,171,174,177,75,183,186,49,17
%N A067722 Least positive integer k such that n*(n + k) is a perfect square.
%H A067722 Peter Kagey, <a href="/A067722/b067722.txt">Table of n, a(n) for n = 0..5000</a>
%e A067722 a(8) = 10 because 8*(8+10) = 144 = 12^2.
%t A067722 Do[k = 1; While[ !IntegerQ[ Sqrt[ k (k + n)]], k++ ]; Print[k], {n, 0, 75} ]
%o A067722 (PARI) a(n) = my(k=1); while(!issquare(n*(n+k)), k++); k; \\ _Michel Marcus_, Feb 05 2015
%o A067722 (Haskell)
%o A067722 a067722 n = head [k | k <- [1..], a010052 (n * (n + k)) == 1]
%o A067722 -- _Reinhard Zumkeller_, Feb 07 2015
%Y A067722 Cf. A010052.
%K A067722 nonn
%O A067722 0,2
%A A067722 _Robert G. Wilson v_, Feb 05 2002