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 A184335 #18 Mar 31 2012 13:22:29 %S A184335 4,6,10,14,20,22,26,28,34,38,42,44,46,50,58,62,74,75,76,78,82,86,90, %T A184335 92,94,106,114,118,122,124,125,134,135,142,146,158,166,172,178,186, %U A184335 188,194,202,204,206,214,218,222,226,236,254,258 %N A184335 Numbers k such that A000001(k) > 1 and A000001(k) | k. %C A184335 Numbers k such that the number of groups of order k (when greater than 1) divides the group order k. I require a proper divisor > 1 because trivially for any p there is 1 group (the cyclic group) of order p, and 1 | p. Even semiprimes A100484 are a proper subset, because when k = p*q for primes p and q, then A000001(k) = 1 if gcd(p,q-1) = 1, 2 if gcd(p,q-1) = p, and (p < q). %H A184335 Nathaniel Johnston, <a href="/A184335/b184335.txt">Table of n, a(n) for n = 1..324</a> %e A184335 a(11) = 42 is in the sequence because there are 6 nonisomorphic groups of order 42, and 42/6 = 7. %e A184335 a(18) = 75 is the first odd value, because there are 5 nonisomorphic groups of order 75, and 75/5 = 15. The next odd value is 125. %Y A184335 Cf. A000001, A100484. %K A184335 nonn,easy %O A184335 1,1 %A A184335 _Jonathan Vos Post_, Feb 13 2011 %E A184335 a(44) - a(52) from _Nathaniel Johnston_, Apr 26 2011