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 A129685 #7 Jul 19 2019 14:26:44 %S A129685 1,0,1,-1,0,1,0,-3,0,1,0,0,-6,0,1,0,0,0,-10,0,1,0,0,0,0,-15,0,1,0,0,0, %T A129685 0,0,-21,0,1,0,0,0,0,0,0,-28,0,1,0,0,0,0,0,0,0,-36,0,1,0,0,0,0,0,0,0, %U A129685 0,-45,0,1 %N A129685 Exponential Riordan array [1-x^2/2, x]. %e A129685 Triangle begins %e A129685 1, %e A129685 0, 1, %e A129685 -1, 0, 1, %e A129685 0, -3, 0, 1, %e A129685 0, 0, -6, 0, 1, %e A129685 0, 0, 0, -10, 0, 1, %e A129685 0, 0, 0, 0, -15, 0, 1, %e A129685 0, 0, 0, 0, 0, -21, 0, 1, %e A129685 0, 0, 0, 0, 0, 0, -28, 0, 1, %e A129685 0, 0, 0, 0, 0, 0, 0, -36, 0, 1, %e A129685 0, 0, 0, 0, 0, 0, 0, 0, -45, 0, 1 %t A129685 (* The function RiordanArray is defined in A256893. *) %t A129685 RiordanArray[1 - #^2/2&, #&, 11, True] // Flatten (* _Jean-François Alcover_, Jul 19 2019 *) %Y A129685 Inverse of A129684. Row sums are A080956. %K A129685 easy,sign,tabl %O A129685 0,8 %A A129685 _Paul Barry_, Apr 28 2007