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 A247646 #9 Jun 29 2016 10:33:19 %S A247646 1,1,3,3,1,1,3,9,5,7,11,1,3,9,15,12,10,9,3,1,1,1,3,9,15,27,16,20,12, %T A247646 14,3,3,1,1 %N A247646 Irregular triangle read by rows, arising in enumeration of lattice paths in strips. %C A247646 It would be nice to have a more explicit definition. %H A247646 Johann Cigler, <a href="http://arxiv.org/abs/1501.04750">Some remarks and conjectures related to lattice paths in strips along the x-axis</a>, arXiv:1501.04750. %e A247646 Triangle begins: %e A247646 1, %e A247646 1,3,3,1, %e A247646 1,3,9,5,7,11, %e A247646 1,3,9,15,12,10,9,3,1,1, %e A247646 1,3,9,15,27,16,20,12,14,3,3,1,1, %e A247646 ... %Y A247646 The diagonals on the left are given by A247643. %K A247646 nonn,tabf,more %O A247646 0,3 %A A247646 _N. J. A. Sloane_, Sep 23 2014