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 A085817 #5 Oct 04 2012 10:28:48 %S A085817 4,6,7,9,12,13,14,15,20,21,22,23,24,30,31,36,38,39,41,44,45,46,47,52, %T A085817 53,54,55,56,62,63,69,70,71,73,76,77,78,79,81,86,87,88,94,95,96,97, %U A085817 101,102,103,105,108,109,110,111,112,118,119,120,126,127,129,132,133,134,135,137 %N A085817 Start at (2n+1)/4 and iterate the map x -> x*ceiling(x); sequence gives values of n for which the denominators in the orbit drop directly from 4 to 1, bypassing 2. %C A085817 No formula is known for these numbers. %H A085817 J. C. Lagarias and N. J. A. Sloane, Approximate squaring (<a href="http://neilsloane.com/doc/apsq.pdf">pdf</a>, <a href="http://neilsloane.com/doc/apsq.ps">ps</a>), Experimental Math., 13 (2004), 113-128. %Y A085817 Complement of A085833. %Y A085817 A073341 gives number of steps until reach an integer. Cf. A085785. %K A085817 nonn %O A085817 1,1 %A A085817 _N. J. A. Sloane_, Aug 16 2003