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 A278221 #7 Nov 19 2016 08:26:41 %S A278221 1,2,4,2,8,6,16,2,4,12,32,6,64,24,12,2,128,6,256,12,36,48,512,6,8,96, %T A278221 4,24,1024,30,2048,2,72,192,24,6,4096,384,144,12,8192,60,16384,48,12, %U A278221 768,32768,6,16,12,288,96,65536,6,72,24,576,1536,131072,30,262144,3072,36,2,216,120,524288,192,1152,60,1048576,6,2097152,6144,12,384,48,240,4194304,12,4 %N A278221 Filtering sequence (related to prime factorization): a(n) = A046523(A122111(n)). %H A278221 Antti Karttunen, <a href="/A278221/b278221.txt">Table of n, a(n) for n = 1..2048</a> %F A278221 a(n) = A046523(A122111(n)). %o A278221 (Scheme) (define (A278221 n) (A046523 (A122111 n))) %Y A278221 Cf. A046523, A122111. %Y A278221 Cf. also A278220. %K A278221 nonn %O A278221 1,2 %A A278221 _Antti Karttunen_, Nov 16 2016