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 A173694 #11 Sep 02 2014 18:46:57
%S A173694 1,2,5,10,15,16,17,20,30,34,37,40,48,51,60,64,68,74,80,85,95,101,102,
%T A173694 111,120,125,135,136,148,170,185,190,192,197,202,204,222,240,247,250,
%U A173694 255,256,257,259,270,272,285,296,303,304,320,323,333,340,351,370,375,380,394,401
%N A173694 Arguments n for which the Carmichael lambda function A002322(n) is a perfect square.
%H A173694 Reinhard Zumkeller, <a href="/A173694/b173694.txt">Table of n, a(n) for n = 1..10000</a>
%F A173694 A010052(A002322(a(n))) = 1. - _Reinhard Zumkeller_, Sep 02 2014
%e A173694 37 is in the sequence because lambda(37) = 36 = 6^2.
%p A173694 for n from 1 to 500 do if issqr(numtheory[lambda](n) ) then printf("%d,",n) ; end if; end do:
%o A173694 (Haskell)
%o A173694 a173694 n = a173694_list !! (n-1)
%o A173694 a173694_list = filter ((== 1) . a010052 . a002322) [1..]
%o A173694 -- _Reinhard Zumkeller_, Sep 02 2014
%Y A173694 Cf. A002322.
%Y A173694 Cf. A010052.
%K A173694 nonn
%O A173694 1,2
%A A173694 _Michel Lagneau_, Nov 25 2010
%E A173694 Definition rephrased - _R. J. Mathar_, Nov 26 2010