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 A121507 #4 Oct 19 2017 03:15:03 %S A121507 220,284,562,1064,1184,1188,1210,1308,1336,1380,1420,1490,1604,1690, %T A121507 1692,1772,1816,1898,2008,2122,2152,2172,2362,2542,2620,2630,2652, %U A121507 2676,2678,2856,2924,2930,2950,2974,3124,3162,3202,3278,3286,3332,3350,3360 %N A121507 Conjectured list of numbers whose aliquot sequence eventually reaches a cycle of length two or more. %C A121507 For some numbers the outcome of the aliquot sequence is unknown. Currently, 276 is the least such. %Y A121507 Cf. A008892, A063769, A063990, A072890, A072891, A098007, A121508. %K A121507 nonn %O A121507 1,1 %A A121507 _Joshua Zucker_, Aug 04 2006 %E A121507 Edited by _Don Reble_, Aug 15 2006