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 A242535 #7 Mar 12 2015 17:59:14 %S A242535 1,3,5,6,8,9,10,12,13,16,17,18,20,21,24,25,27,28,29,32,33,35,36,37,39, %T A242535 41,42,44,45,48,49,50,53,54,56,57,58,59,61,63,65,66,67,70,71,73,74,76, %U A242535 77,78,79,82,83,85,87,88,90,91,93,95,97,98,99,101,103 %N A242535 Start with the natural numbers and repeatedly take and keep the current initial term i, and remove m and 2m, where m = i-th term of the rest; repeat. %H A242535 Reinhard Zumkeller, <a href="/A242535/b242535.txt">Table of n, a(n) for n = 1..10000</a> %H A242535 <a href="/index/Si#sieve">Index entries for sequences generated by sieves</a> %e A242535 Start with 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,... %e A242535 step 1: take 1, remove (1st term from the rest) = 2 and 2*2 = 4, %e A242535 leaving 3,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26... %e A242535 step 2: take 3, remove (3rd term from the rest) = 7 and 2*7 = 14, %e A242535 leaving 5,6,8,9,10,11,12,13,15,16,17,18,19,20,21,22,23,24,25,26,27,28,... %e A242535 step 3: take 5, remove (5th term from the rest) = 11 and 2*11 = 22, %e A242535 leaving 6,8,9,10,12,13,15,16,17,18,19,20,21,23,24,25,26,27,28,29,30,... %e A242535 step 4: take 6, remove (6th term from the rest) = 15 and 2*15 = 30, %e A242535 leaving 8,9,10,12,13,16,17,18,19,20,21,23,24,25,26,27,28,29,31,32,33,... %e A242535 step 5: take 8, remove (8th term from the rest) = 19 and 2*19 = 38, %e A242535 leaving 9,10,12,13,16,17,18,20,21,23,24,25,26,27,28,29,31,32,33,34,35,... %e A242535 step 6: take 9, remove (9th term from the rest) = 23, and 2*23 = 46, %e A242535 leaving 10,12,13,16,17,18,20,21,24,25,26,27,28,29,31,32,33,34,35,36,... %o A242535 (Haskell) %o A242535 import Data.List ((\\)) %o A242535 a242535 n = a242535_list !! (n-1) %o A242535 a242535_list = f [1..] where %o A242535 f xs'@(x:xs) = x : f (xs \\ [z, 2 * z]) where z = xs' !! x %Y A242535 Cf. A136119. %K A242535 nonn %O A242535 1,2 %A A242535 _Reinhard Zumkeller_, May 17 2014