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 A102251 #10 Mar 29 2015 16:33:49 %S A102251 1,2,4,8,16,2,12,4,2,4,8,4,8,16,8,16,2,12,16,2,12,4,2,4,2,12,4,2,4,8, %T A102251 4,8,4,2,4,8,4,8,16,8,16,8,4,8,16,8,16,2,12,16,2,12,16,8,16,2,12,16,2, %U A102251 12,4,2,4,2,12,4,2,4,2,12,16,2,12,4,2,4,2,12,4,2,4,8,4,8,4,2,4,8,4,8,4,2,4 %N A102251 Begin with 1, multiply each digit by 2. %C A102251 Same digits as A061581 without the memory of the groupings of the preceding digits. A bunch of sequences can be produced with this rule: a(n)=d*k beginning with 1,2,3... for k=2,3,... %H A102251 Reinhard Zumkeller, <a href="/A102251/b102251.txt">Table of n, a(n) for n = 0..10000</a> %F A102251 d*2, beginning with 1 %e A102251 Read a(5)=16 which produces a(6)=2 because 1*2=2 and a(7)=12 because 6*2=12. Now read a(6)=2 which produces [a(7) is already written] a(8)=4 because 2*2=4. %t A102251 Flatten[ NestList[ Function[x, Flatten[ FromDigits /@ 2IntegerDigits[ x]]], 1, 15]] (* _Robert G. Wilson v_, Feb 21 2005 *) %o A102251 (Haskell) %o A102251 a102251 n = a102251_list !! n %o A102251 a102251_list = 1 : (map (* 2) $ %o A102251 concatMap (map (read . return) . show) a102251_list) %o A102251 -- _Reinhard Zumkeller_, Oct 02 2014 %Y A102251 Cf. A061581. %Y A102251 Cf. A248131. %K A102251 base,easy,nonn %O A102251 0,2 %A A102251 _Alexandre Wajnberg_ and _Eric Angelini_, Feb 18 2005 %E A102251 More terms from _Robert G. Wilson v_, Feb 21 2005