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 A128686 #9 Jan 31 2017 12:27:43 %S A128686 3,9,8,24,32,64,128,864,1792,1536,2048,4096,8192,24576,73728,98304, %T A128686 131072,393216,524288,1048576,3145728,6291456,8388608,37748736, %U A128686 50331648,150994944,301989888,268435456,1207959552,1610612736,2147483648,4294967296,19327352832,25769803776,115964116992,171798691840,343597383680,927712935936,2886218022912,1099511627776,20890720927744,24189255811072 %N A128686 Least number of the form semiprime - 1 which is the product of exactly n primes. %Y A128686 Cf. A005383, A070552, A128665. %K A128686 nonn %O A128686 1,1 %A A128686 _Ray Chandler_, Mar 20 2007 %E A128686 a(27)-a(42) from _Donovan Johnson_, Nov 24 2010