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 A120616 #13 Aug 22 2025 10:55:03
%S A120616 1,0,-1,-2,0,1,0,3,0,-1,6,0,-4,0,1,0,-10,0,5,0,-1,-20,0,15,0,-6,0,1,0,
%T A120616 35,0,-21,0,7,0,-1,70,0,-56,0,28,0,-8,0,1,0,-126,0,84,0,-36,0,9,0,-1,
%U A120616 -252,0,210,0,-120,0,45,0,-10,0,1
%N A120616 Generalized Riordan array (1/sqrt(1+4x^2),(1-sqrt(1+4x^2))/(2x)).
%C A120616 Product by A007318 is A104505.
%H A120616 Michael De Vlieger, <a href="/A120616/b120616.txt">Table of n, a(n) for n = 0..11475</a> (rows n = 0..150, flattened.)
%H A120616 Robert S. Maier, <a href="https://arxiv.org/abs/2508.13094">Sheffer Polynomials and the s-ordering of Exponential Boson Operators</a>, arXiv:2508.13094 [quant-ph], 2025. See p. 27.
%F A120616 Number triangle T(n,k)=C(n,(n+k)/2)(-1)^((n+k)/2)(1+(-1)^(n+k))/2.
%F A120616 abs(T(n,k)) = A108044(n,k).
%e A120616 Triangle begins
%e A120616 1;
%e A120616 0, -1;
%e A120616 -2, 0, 1;
%e A120616 0, 3, 0, -1;
%e A120616 6, 0, -4, 0, 1;
%e A120616 0, -10, 0, 5, 0, -1;
%e A120616 -20, 0, 15, 0, -6, 0, 1;
%e A120616 0, 35, 0, -21, 0, 7, 0, -1;
%e A120616 70, 0, -56, 0, 28, 0, -8, 0, 1;
%e A120616 0, -126, 0, 84, 0, -36, 0, 9, 0, -1;
%e A120616 -252, 0, 210, 0, -120, 0, 45, 0, -10, 0, 1;
%t A120616 T[n_, k_] := Binomial[n, (n + k)/2]*(-1)^((n + k)/2) (1 + (-1)^(n + k))/2; Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* _Michael De Vlieger_, Aug 22 2025 *)
%K A120616 easy,sign,tabl,changed
%O A120616 0,4
%A A120616 _Paul Barry_, Jun 17 2006