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 A060700 #12 Mar 31 2018 15:05:55
%S A060700 15,30,35,45,63,70,75,77,91,99,105,117,126,135,140,143,150,153,154,
%T A060700 165,175,182,187,189,195,198,209,221,225,231,234,245,247,252,255,273,
%U A060700 280,285,286,297,299,306,308,315,323,325,330,345,350,351,357,364,374,375
%N A060700 "Anomalous" numbers k such that for even numbers 2k, gcd(2k, lcm(dd(2k)))=2k and not k, where dd(2k) is the first difference set of divisors of 2k.
%e A060700 63 is here because for 126 = 2*63, lcm(dd(126)) = lcm(1, 1, 3, 1, 2, 5, 4, 3, 21, 21, 63) = 1260, so gcd(126, lcm(dd(126))) = gcd(126, 1260) = 126.
%o A060700 (PARI) f(n) = {my(d = divisors(n), dd = vector(#d-1, k, d[k+1] - d[k])); gcd(n, lcm(dd));}
%o A060700 isok(n) = (f(2*n) == 2*n); \\ _Michel Marcus_, Mar 29 2018
%Y A060700 Cf. A060680, A060681, A060682, A060683, A060684, A060685, A060741, A060742, A060763, A060764, A060765, A060766, A000005.
%K A060700 nonn
%O A060700 1,1
%A A060700 _Labos Elemer_, Apr 25 2001