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 A177457 #28 Feb 03 2023 03:16:41 %S A177457 0,1,1,-1,1,1,0,1,-1,1,1,1,2,-1,1,-1,1,1,2,3,0,3,-2,1,-1,1,1,3,4,2,6, %T A177457 -2,4,-3,1,-1,1,1,4,5,5,10,0,10,-5,5,-4,1,-1,1,1,5,6,9,15,5,20,-5,15, %U A177457 -9,6,-5,1,-1,1,1,6,7,14,21,14,35,0,35,-14,21,-14,7,-6,1,-1,1,1,7,8,20,28 %N A177457 Triangle read by rows; union of A007318 and A112467. %F A177457 T(n, k) = T(n-1, k-1) + T(n-1, k+1), for n > 2 and T(n, k) = 0 for negative k or k > 2*n-1. - _Thomas Scheuerle_, Feb 02 2023 %e A177457 Triangle begins: %e A177457 0 %e A177457 1 1 -1 %e A177457 1 1 0 1 -1 %e A177457 1 1 1 2 -1 1 -1 %e A177457 1 1 2 3 0 3 -2 1 -1 %e A177457 1 1 3 4 2 6 -2 4 -3 1 -1 %o A177457 (MATLAB) %o A177457 function a = A177457( max_row ) %o A177457 a = [0 1 1 -1]; %o A177457 for n = 3:max_row %o A177457 r = [0 0 a(end-((n-2)*2):end) 0 0]; %o A177457 a = [a r(1:end-2)+r(3:end)]; %o A177457 end %o A177457 end % _Thomas Scheuerle_, Feb 02 2023 %Y A177457 Cf. A007318, A112467. %K A177457 tabf,sign %O A177457 1,13 %A A177457 _Mark Dols_, May 09 2010 %E A177457 More terms from _Thomas Scheuerle_, Feb 02 2023