cp's OEIS Frontend

A198889 Square array in A071223 read by antidiagonals.

%I A198889 #15 May 10 2019 21:42:34
%S A198889 2,2,2,2,6,2,2,12,6,2,2,20,24,6,2,2,30,72,24,6,2,2,42,172,120,24,6,2,
%T A198889 2,56,352,480,120,24,6,2,2,72,646,1512,720,120,24,6,2,2,90,1094,3976,
%U A198889 3600,720,120,24,6,2,2,110,1742,9144,14184,5040,720,120,24,6,2,2,132,2642,18990,45992,30240,5040,720,120
%N A198889 Square array in A071223 read by antidiagonals.
%H A198889 T. M. Cover, <a href="http://www.jstor.org/stable/2946294">The number of linearly inducible orderings of points in d-space</a>, SIAM J. Applied Math., 15 (1967), 434-439.
%F A198889 See A071223, which is the main entry for this array.
%e A198889 Array begins
%e A198889   2  2   2   2   2  ...
%e A198889   2  6   6   6   6 ...
%e A198889   2 12  24  24  24 ...
%e A198889   2 20  72 120 120 ...
%e A198889   2 30 172 480 720 ...
%e A198889   ...
%p A198889 A071223 := proc(n,k)
%p A198889         if k=1 and n>=2 then
%p A198889                 2
%p A198889         elif n=2 and k>=1 then
%p A198889                 2
%p A198889         elif k>=n-1 then
%p A198889                 n!
%p A198889         else
%p A198889         procname(n-1, k)+(n-1)*procname(n-1, k-1)
%p A198889         fi ;
%p A198889 end proc:
%p A198889 for d from 3 to 16 do
%p A198889         for k from 1 to d-2 do
%p A198889                 n := d-k ;
%p A198889                 printf("%d,",A071223(n,k)) ;
%p A198889         end do:
%p A198889 end do; # _R. J. Mathar_, Oct 31 2011
%Y A198889 Cf. A071223.
%K A198889 nonn,tabl
%O A198889 2,1
%A A198889 _N. J. A. Sloane_, Oct 30 2011