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 A327809 #10 Sep 26 2019 08:07:22 %S A327809 -1,3,2,-10,-15,-6,35,84,70,20,-126,-420,-540,-315,-70,462,1980,3465, %T A327809 3080,1386,252,-1716,-9009,-20020,-24024,-16380,-6006,-924,6435,40040, %U A327809 108108,163800,150150,83160,25740,3432,-24310,-175032,-556920,-1021020,-1178100,-875160,-408408,-109395,-12870 %N A327809 Regular triangle, coefficients of the polynomial P(n)(x) = (-1)^(n+1)*(2*n+1)*binomial(2*n, n)*Sum_{i=0..n} x^i*binomial(n, i)/(n+i+1). %H A327809 Karl Dilcher, Maciej Ulas, <a href="https://arxiv.org/abs/1909.11222">Arithmetic properties of polynomial solutions of the Diophantine equation P(x)x^(n+1)+Q(x)(x+1)^(n+1)=1</a>, arXiv:1909.11222 [math.NT], 2019. See Pn(x) Table 1 p. 2. %e A327809 Triangle begins: %e A327809 -1; %e A327809 3, 2; %e A327809 -10, -15, -6; %e A327809 35, 84, 70, 20; %e A327809 -126, -420, -540, -315, -70; %e A327809 462, 1980, 3465, 3080, 1386, 252; %e A327809 -1716, -9009, -20020, -24024, -16380, -6006, -924; %e A327809 ... %o A327809 (PARI) pol(n) = (-1)^(n+1)*(2*n+1)*binomial(2*n, n)*sum(i=0, n, x^i*binomial(n, i)/(n+i+1)); %o A327809 row(n) = Vecrev(pol(n)); %o A327809 tabl(nn) = for (n=0, nn, print(row(n))); %Y A327809 Cf. A046899 (Q(x) polynomials, up to sign). %Y A327809 Cf. A001700 (1st column, up to sign), A033876 (right diagonal, up to sign). %K A327809 sign,tabl %O A327809 0,2 %A A327809 _Michel Marcus_, Sep 26 2019