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 A169755 #7 Apr 09 2014 23:44:31 %S A169755 1,3,2,5,9,4,10,8,15,7,16,6,17,14,26,13,27,12,28,11,29,25,20,39,19,40, %T A169755 18,41,35,59,34,60,33,61,32,62,31,24,56,23,57,22,58,21,29,67,106,66, %U A169755 107,65,108,64,55,45,90,44,91,43,92,42,93,82,30,83,71,125,70,126,69,127,68 %N A169755 A variation on Recamán's sequence A005132: see Comments for definition. %C A169755 We start with two sequences A and B. Here sequences A and B are both taken to be 1,2,3,4,5,6,7,.... %C A169755 We start with the first term of sequence A (which is 1). %C A169755 To extend the sequence, we first try to subtract the next term of A from the current term, but that is allowed only if the result is a positive number not already in the sequence. %C A169755 If that fails, we next try to subtract the next term of B from the current term, but again that is allowed only if the result is a positive number not already in the sequence. %C A169755 If that fails, we next try to add the next term of A to the current term, but again that is allowed only if the result is a positive number not already in the sequence. %C A169755 Finally, if that fails, we add the next term of B to the current term (this may produce repeated terms, but that is allowed at this step). %Y A169755 Cf. A005132, A169748-A169752. %K A169755 nonn %O A169755 1,2 %A A169755 _Rodolfo Kurchan_, Apr 08 2010 %E A169755 Corrected and extended by _D. S. McNeil_, May 09 2010