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A198889 Square array in A071223 read by antidiagonals. 1
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, 2, 56, 352, 480, 120, 24, 6, 2, 2, 72, 646, 1512, 720, 120, 24, 6, 2, 2, 90, 1094, 3976, 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 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..76.

T. M. Cover, The number of linearly inducible orderings of points in d-space, SIAM J. Applied Math., 15 (1967), 434-439.

FORMULA

See A071223, which is the main entry for this array.

EXAMPLE

Array begins

2 2 2 2 2  ...

2 6 6 6 6 ...

2 12 24 24 24 ...

2 20 72 120 120 ...

2 30 172 480 720 ...

....

MAPLE

A071223 := proc(n, k)

        if k=1 and n>=2 then

                2

        elif n=2 and k>=1 then

                2

        elif k>=n-1 then

                n!

        else

        procname(n-1, k)+(n-1)*procname(n-1, k-1)

        fi ;

end proc:

for d from 3 to 16 do

        for k from 1 to d-2 do

                n := d-k ;

                printf("%d, ", A071223(n, k)) ;

        end do:

end do; # R. J. Mathar, Oct 31 2011

CROSSREFS

Cf. A071223.

Sequence in context: A278260 A070877 A156717 * A130754 A164126 A261902

Adjacent sequences:  A198886 A198887 A198888 * A198890 A198891 A198892

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Oct 30 2011

STATUS

approved

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Last modified March 24 06:56 EDT 2019. Contains 321444 sequences. (Running on oeis4.)