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 A171177 #2 Mar 30 2012 17:34:03 %S A171177 2,-1,5,-3,2,-1,8,-5,4,-3,2,-1,11,-7,6,-5,4,-3,2,-1,14,-9,8,-7,6,-5,4, %T A171177 -3,2,-1,17,-11,10,-9,8,-7,6,-5,4,-3,2,-1,20,-13,12,-11,10,-9,8,-7,6, %U A171177 -5,4,-3,2,-1,23,-15,14,-13,12,-11,10,-9,8,-7,6,-5,4,-3,2,-1,26,-17,16,-15 %N A171177 Triangle read by rows in which row n lists 3n-1 together with the first 2n-1 numbers <> 0 of A038608, in reverse order. %C A171177 Absolute values give A171176. %C A171177 Note that the partial sums of this sequence give A171178, a permutation of the natural numbers. %e A171177 Triangle begins: %e A171177 2, -1; %e A171177 5, -3, 2, -1; %e A171177 8, -5, 4, -3, 2, -1; %e A171177 11,-7, 6, -5, 4, -3, 2, -1; %e A171177 14,-9, 8, -7, 6, -5, 4, -3, 2, -1; %e A171177 17,-11,10,-9, 8, -7, 6, -5, 4, -3, 2, -1; %e A171177 20,-13,12,-11,10,-9, 8, -7, 6, -5, 4, -3, 2, -1; %e A171177 23,-15,14,-13,12,-11,10,-9, 8, -7, 6, -5, 4, -3, 2, -1; %e A171177 26,-17,16,-15,14,-13,12,-11,10,-9, 8, -7, 6, -5, 4, -3, 2, -1; %Y A171177 Cf. A016789, A038608, A172310, A171164, A161165, A161166, A171172, A171173, A171174, A171175, A171176, A171178. %K A171177 easy,sign,tabf %O A171177 1,1 %A A171177 _Omar E. Pol_, Feb 23 2010