A137948 - OEIS

%I #11 Apr 02 2022 14:22:13

%S 1,2,1,3,2,2,4,3,4,6,5,4,6,12,24,6,5,8,18,48,120,7,6,10,24,72,240,720,

%T 8,7,12,30,96,360,1440,5040,9,8,14,36,120,480,2160,10080,40320,10,9,

%U 16,42,144,600,2880,15120,80640,362880

%N Triangle read by rows, A000012 * A136579.

%C Row sums = A014144 starting (1, 3, 7, 17, 51, 205, ...).

%C T(n,k) = A245334(n,k) / A007318(n,k), 0 <= k <= n. - _Reinhard Zumkeller_, Aug 31 2014

%H Reinhard Zumkeller, <a href="/A137948/b137948.txt">Rows n = 0..125 of triangle, flattened</a>

%F As infinite lower triangular matrices, A000012 * A136579, where A000012 = (1; 1,1; 1,1,1; ...) and A136579 = (1; 1,1; 1,1,2; 1,1,2,6; 1,1,2,6,24; ...).

%F T(n,k) = (n+1-k) * k! for 0 <= k <= n. - _Werner Schulte_, Oct 06 2020

%e First few rows of the triangle:

%e   1;

%e   2, 1;

%e   3, 2,  2;

%e   4, 3,  4,  6;

%e   5, 4,  6, 12, 24;

%e   6, 5,  8, 18, 48, 120;

%e   7, 6, 10, 24, 72, 240, 720;

%e   ...

%o (Haskell)

%o a137948 n k = a137948_tabl !! n !! k

%o a137948_row n = a137948_tabl !! n

%o a137948_tabl = zipWith (zipWith div) a245334_tabl a007318_tabl

%o -- _Reinhard Zumkeller_, Aug 31 2014

%Y Cf. A136579, A014144.

%Y Cf. A245334, A007318.

%K nonn,tabl

%O 0,2

%A _Gary W. Adamson_, Feb 28 2008

%E Offset changed by _Reinhard Zumkeller_, Aug 31 2014