a(n,m) asociated Sheffer triangle A111596 (assciated to Sheffer triangle A111595) n\m 0 1 2 3 4 5 6 7 8 9 ... 0 1 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 2 0 -2 1 0 0 0 0 0 0 0 3 0 6 -6 1 0 0 0 0 0 0 4 0 -24 36 -12 1 0 0 0 0 0 5 0 120 -240 120 -20 1 0 0 0 0 6 0 -720 1800 -1200 300 -30 1 0 0 0 7 0 5040 -15120 12600 -4200 630 -42 1 0 0 8 0 -40320 141120 -141120 58800 -11760 1176 -56 1 0 9 0 362880 -1451520 1693440 -846720 211680 -28224 2016 -72 1 . . . ############################################################################################################# Added April 12, 2007: The unsigned triangle |a(n,m)| is the matrix product of the lower triangular Stirling number matrices |S1|*S2. (remember that S1*S2=S2*S1=1(matrix)). |a(n,m)|=sum(|S1(n,k)|*S2(k,m),k=m..n), n>=0. S2(n,m):=A048993. S1(n,m):=A048994. This follows from the Jabotinsky type of the Stirling number matrices. See the D. E. Knuth reference given in A039692 for Jabotinsky type matrices. |S1| has the e.g.f. of the m=1 column -ln(1-x) and S2 has the e.g.f. of the m=1 column exp(x)-1. Therefore, the matrix product |S1|*S2, which is again of the Jabotinsky type, has corresponding e.g.f. exp(-ln(1-x))-1 = x/(1-x). This means that the e.g.f. for the row polynomials of P(n,x):=sum(|a(n,m)|*x^m,m=0..n) is exp(x*z/(1-z)). As a Jobotinsky matrix |a(n,m)| has the e.g.f. for column nr. m: (f(x)^m)/m! with f(x):= x/(1-x). ########################################### e.o.f. ###########################################################