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 A057921 #9 May 29 2015 15:13:16
%S A057921 2,6,10,12,14,18,21,22,26,28,30,33,34,38,40,42,44,46,52,54,56,57,58,
%T A057921 60,66,70,72,75,78,80,82,84,85,86,88,90,93,94,96,98,102,104,105,106,
%U A057921 108,110,112,114,116,118,122,126,128,130,132,133,135,136,138,140,141,142
%N A057921 d(n+1) divides d(n), where d(n) is number of positive divisors of n.
%H A057921 Ivan Neretin, <a href="/A057921/b057921.txt">Table of n, a(n) for n = 0..10000</a>
%e A057921 10 is included because d(11) = 2 divides d(10) = 4.
%t A057921 Select[Range@150, Divisible @@ DivisorSigma[0, {#, # + 1}] &] (* _Ivan Neretin_, May 29 2015 *)
%Y A057921 Cf. A057922, A005237.
%K A057921 nonn
%O A057921 0,1
%A A057921 _Leroy Quet_, Nov 11 2000