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 A052173 #19 Jan 05 2025 19:51:36 %S A052173 1,1,0,1,0,1,1,0,2,0,1,0,3,0,2,1,0,4,0,5,0,1,0,5,0,9,0,5,1,0,6,0,14,0, %T A052173 14,0,1,0,7,0,20,0,28,0,14,1,0,8,0,27,0,48,0,42,0,1,0,9,0,35,0,75,0, %U A052173 90,0,42,1,0,10,0,44,0,110,0,165,0,132,0,1,0,11,0,54,0,154,0,275,0,297,0 %N A052173 Another version of the Catalan triangle A008315. %H A052173 R. K. Guy, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL3/GUY/catwalks.html">Catwalks, sandsteps and Pascal pyramids</a>, J. Integer Sequences, Vol. 3 (2000), Article #00.1.6 %H A052173 W. F. Klostermeyer, M. E. Mays, L. Soltes and G. Trapp, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/35-4/klostermeyer.pdf">A Pascal rhombus</a>, Fibonacci Quarterly, 35 (1997), 318-328. %F A052173 a(n, k) = a(n-1, k-2)+a(n-1, k) with a(0, 0)=1 and a(n, k)=0 if k < 0 or k > n. %e A052173 1; %e A052173 1 0; %e A052173 1 0 1; %e A052173 1 0 2 0; %e A052173 1 0 3 0 2; %e A052173 1 0 4 0 5 0; %e A052173 1 0 5 0 9 0 5; %e A052173 ... %Y A052173 See A008315 (the main entry for this triangle) for more information. %Y A052173 Reflection of A053121. %K A052173 nonn,easy,tabl %O A052173 0,9 %A A052173 _N. J. A. Sloane_, Jan 26 2000 %E A052173 More terms from _Henry Bottomley_, Aug 23 2001