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 A048743 #12 Jul 02 2025 16:01:57 %S A048743 1,1,2,1,12,6,1,42,108,24,1,120,900,960,120,1,310,5400,15600,9000,720, %T A048743 1,756,27090,168000,252000,90720,5040,1,1778,121716,1428840,4410000, %U A048743 4021920,987840,40320,1,4080,508200,10442880,58388400,106686720 %N A048743 Triangle a(n,k) = k!*C(n-1,k-1)*Stirling_2(n,k), 1<=k<=n. %e A048743 The 3rd row is formed from [ 1,2,6,24 ]*[ 1,3,3,1 ]*[ 1,7,6,1 ] => [ 1,42,108,24 ]. %e A048743 1; %e A048743 1,2; %e A048743 1,12,6; %e A048743 1,42,108,24; %e A048743 1,120,900,960,120; %p A048743 A048743 := proc(n,k) k!*binomial(n-1,k-1)*combinat[stirling2](n,k) ; end proc: %p A048743 seq(seq(A048743(n,k),k=1..n),n=1..12) ; # _R. J. Mathar_, Aug 30 2011 %t A048743 Flatten[Table[k!Binomial[n-1,k-1]StirlingS2[n,k],{n,10},{k,n}]] (* _Harvey P. Dale_, Feb 21 2013 *) %Y A048743 Cf. A007318, A008277. Row sums give A045531. %K A048743 easy,nonn,tabl %O A048743 1,3 %A A048743 _Alford Arnold_ %E A048743 More terms from _James Sellers_, Apr 22 2000