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%I
%S 1,2,4,6,12,18,24,48,72,96,120,240,360,480,600,720,1440,2160,2880,
%T 3600,4320,5040,10080,15120,20160,25200,30240,35280,40320,80640,
%U 120960,161280,201600,241920,282240,322560,362880,725760,1088640,1451520
%N Triangle read by rows: a(n,k)=n!*k.
%C Numbers with only one non-zero digit when written in base factorial. - Franklin T. Adams-Watters, Nov 28 2011.
%H _Reinhard Zumkeller_, <a href="/A051683/b051683.txt">Rows n=1..150 of triangle, flattened</a>
%H Tilman Piesk, <a href="http://en.wikiversity.org/wiki/Inversion_%28discrete_mathematics%29#arrays4">Arrays of permutations</a>
%e Table begins
%e 1
%e 2 4
%e 6 12 18
%e 24 48 72 96 ...
%t a[n_, k_] := n!*k; Flatten[Table[a[n, k], {n, 9}, {k, n}]] (* From Jean-François Alcover, Apr 22 2011 *)
%o (Haskell)
%o a051683 n k = a051683_tabl !! (n-1) !! (k-1)
%o a051683_row n = a051683_tabl !! (n-1)
%o a051683_tabl = map fst $ iterate f ([1], 2) where
%o f (row, n) = (row' ++ [head row' + last row'], n + 1) where
%o row' = map (* n) row
%o -- _Reinhard Zumkeller_, Mar 09 2012
%Y Cf. A000142, row sums give A001286(n+1).
%Y Cf. A200748.
%Y Cf. A162608.
%K easy,nice,nonn,tabl
%O 1,2
%A Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de)
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