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 A136595 #19 Mar 23 2020 17:29:58 %S A136595 1,0,1,0,-1,1,0,7,-3,1,0,-61,31,-6,1,0,751,-375,85,-10,1,0,-11821, %T A136595 5911,-1350,185,-15,1,0,226927,-113463,26341,-3710,350,-21,1,0, %U A136595 -5142061,2571031,-603246,87381,-8610,602,-28,1,0,134341711,-67170855,15887845,-2346330,240051,-17766 %N A136595 Matrix inverse of triangle A136590. %C A136595 A136590 is the triangle of trinomial logarithmic coefficients. %C A136595 Column 1 is signed A048287, which is the number of semiorders on n labeled nodes whose incomparability graph is connected. %C A136595 The Bell transform of (-1)^n*A048287(n+1). For the definition of the Bell transform see A264428. - _Peter Luschny_, Jan 18 2016 %F A136595 T(n,k) = Sum_{i=0..n-1} (-1)^i * (k+i)! * Stirling2(n,k+i) * Catalan(k,i)/k!, where Stirling2(n,k) = A008277(n,k); Catalan(k,i) = C(2i+k,i)*k/(2i+k) = coefficient of x^i in C(x)^k with C(x) = (1-sqrt(1-4x))/(2x). %e A136595 Triangle begins: %e A136595 1; %e A136595 0, 1; %e A136595 0, -1, 1; %e A136595 0, 7, -3, 1; %e A136595 0, -61, 31, -6, 1; %e A136595 0, 751, -375, 85, -10, 1; %e A136595 0, -11821, 5911, -1350, 185, -15, 1; %e A136595 0, 226927, -113463, 26341, -3710, 350, -21, 1; %e A136595 0, -5142061, 2571031, -603246, 87381, -8610, 602, -28, 1; %e A136595 0, 134341711, -67170855, 15887845, -2346330, 240051, -17766, 966, -36, 1; ... %p A136595 # The function BellMatrix is defined in A264428. %p A136595 BellMatrix(n -> (-1)^n*A048287(n+1), 9); # _Peter Luschny_, Jan 27 2016 %t A136595 BellMatrix[f_Function, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]]; %t A136595 rows = 11; %t A136595 M = BellMatrix[Sum[(-1)^(k+1) k! StirlingS2[#+1, k] CatalanNumber[k-1], {k, 1, #+1}]&, rows]; %t A136595 Table[M[[n, k]], {n, 1, rows}, {k, 1, n}] // Flatten (* _Jean-François Alcover_, Jun 24 2018, after _Peter Luschny_ *) %o A136595 (PARI) {T(n,k) = if(n<k||k<0,0,if(n==k,1,if(k==0,0,n!/(k-1)!* sum(i=0,n-1,(-1)^i * polcoeff(((exp(x + x*O(x^n)) - 1)^(k+i)),n) * binomial(2*i+k,i)/(2*i+k)))))} %o A136595 for(n=0,10,for(k=0,n,print1(T(n,k),", "));print("")) %o A136595 (PARI) /* Define Stirling2: */ %o A136595 {Stirling2(n,k) = n!*polcoeff(((exp(x+x*O(x^n))-1)^k)/k!,n)} %o A136595 /* Define Catalan(m,n) = [x^n] C(x)^m: */ %o A136595 {CATALAN(m,n) = binomial(2*n+m,n) * m/(2*n+m)} %o A136595 /* Define this triangle: */ %o A136595 {T(n,k) = if(n<k||k<0,0,if(n==k,1,if(k==0,0, sum(i=0,n-1,(-1)^i*(k+i)!*Stirling2(n,k+i) * CATALAN(k,i)/k!))))} %o A136595 for(n=0,10,for(k=0,n,print1(T(n,k),", "));print("")) %o A136595 (Sage) # uses[bell_matrix from A264428] %o A136595 bell_matrix(lambda n: (-1)^n*A048287(n+1), 10) # _Peter Luschny_, Jan 18 2016 %Y A136595 Cf. columns: A048287, A136596, A136597; A136590 (matrix inverse); A136588, A136589. %K A136595 sign,tabl %O A136595 0,8 %A A136595 _Paul D. Hanna_, Jan 10 2008