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 A112239 #7 Jun 13 2017 22:38:44 %S A112239 0,0,0,1,-2,0,3,3,-6,0,12,12,6,-12,0,60,60,30,10,-20,0,360,360,180,60, %T A112239 15,-30,0,2520,2520,1260,420,105,21,-42,0,20160,20160,10080,3360,840, %U A112239 168,28,-56,0,181440,181440,90720,30240,7560,1512,252,36,-72,0 %N A112239 Matrix logarithm of triangle A111595. %C A112239 A111595 is the triangle of coefficients of square of Hermite polynomials divided by 2^n with argument sqrt(x/2). %F A112239 T(n, k) = n!/k!/2 for n-1>k>=0; T(k+1, k) = -k*(k+1), T(k, k) = 0 for k>=0. %e A112239 Triangle begins: %e A112239 0; %e A112239 0,0; %e A112239 1,-2,0; %e A112239 3,3,-6,0; %e A112239 12,12,6,-12,0; %e A112239 60,60,30,10,-20,0; %e A112239 360,360,180,60,15,-30,0; %e A112239 2520,2520,1260,420,105,21,-42,0; %e A112239 20160,20160,10080,3360,840,168,28,-56,0; ... %o A112239 (PARI) T(n,k)=if(n<=k || k<0,0,if(n-1==k,-k*(k+1),n!/k!/2)) %Y A112239 Cf. A112239. %K A112239 sign,tabl %O A112239 0,5 %A A112239 _Paul D. Hanna_, Aug 29 2005