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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
OFFSET
2,1
LINKS
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 * A329814 A130754 A164126
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Oct 30 2011
STATUS
approved