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 A155727 #9 Apr 02 2019 05:43:11 %S A155727 0,1,3,-1,1,5,0,-1,1,7,0,0,-1,1,9,0,0,0,-1,1,11,0,0,0,0,-1,1,13,0,0,0, %T A155727 0,0,-1,1,15,0,0,0,0,0,0,-1,1,17,0,0,0,0,0,0,0,-1,1 %N A155727 Production matrix of the Jacobsthal numbers, read by row. %C A155727 The matrix generated by the matrix has row sums A001045(n+1). %H A155727 E. Deutsch, L. Ferrari and S. Rinaldi, <a href="https://doi.org/10.1016/j.aam.2004.05.002">Production Matrices</a>, Advances in Applied Mathematics, 34 (2005) pp. 101-122. %e A155727 Matrix begins %e A155727 0, 1, %e A155727 3, -1, 1, %e A155727 5, 0, -1, 1, %e A155727 7, 0, 0, -1, 1, %e A155727 9, 0, 0, 0, -1, 1, %e A155727 11, 0, 0, 0, 0, -1, 1, %e A155727 13, 0, 0, 0, 0, 0, -1, 1, %e A155727 15, 0, 0, 0, 0, 0, 0, -1, 1, %e A155727 17, 0, 0, 0, 0, 0, 0, 0, -1, 1 %Y A155727 Cf. A001045, A155726. %K A155727 sign,tabf %O A155727 0,3 %A A155727 _Paul Barry_, Jan 25 2009