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 A171174 #2 Mar 30 2012 17:34:03 %S A171174 2,-1,4,-1,2,-3,7,-1,2,-3,4,-5,10,-1,2,-3,4,-5,6,-7,13,-1,2,-3,4,-5,6, %T A171174 -7,8,-9,16,-1,2,-3,4,-5,6,-7,8,-9,10,-11,19,-1,2,-3,4,-5,6,-7,8,-9, %U A171174 10,-11,12,-13,22,-1,2,-3,4,-5,6,-7,8,-9,10,-11,12,-13,14,-15,25,-1,2,-3,4 %N A171174 Triangle read by rows in which row n lists A033627(n) together with the first 2n-1 numbers <> 0 of A038608. %C A171174 Absolute values give A171173. %C A171174 Note that the partial sums of this sequence gives A171175, a permutation of the natural numbers. %e A171174 Triangle begins: %e A171174 2, -1, %e A171174 4, -1,2,-3, %e A171174 7, -1,2,-3,4,-5, %e A171174 10,-1,2,-3,4,-5,6,-7, %e A171174 13,-1,2,-3,4,-5,6,-7,8,-9, %e A171174 16,-1,2,-3,4,-5,6,-7,8,-9,10,-11, %e A171174 19,-1,2,-3,4,-5,6,-7,8,-9,10,-11,12,-13, %e A171174 22,-1,2,-3,4,-5,6,-7,8,-9,10,-11,12,-13,14,-15, %e A171174 25,-1,2,-3,4,-5,6,-7,8,-9,10,-11,12,-13,14,-15,16,-17, %Y A171174 Cf. A033627, A038608, A172310, A171164, A161165, A161166, A171172, A171173, A171175, A171176, A171177, A171178. %K A171174 easy,sign,tabf %O A171174 1,1 %A A171174 _Omar E. Pol_, Feb 23 2010