A127626 - OEIS

%I #8 Jan 21 2014 16:31:28

%S 1,1,3,1,0,5,1,3,0,8,1,0,0,0,9,1,3,5,0,0,15,1,0,0,0,0,0,13,1,3,0,8,0,

%T 0,0,20,1,0,5,0,0,0,0,0,21,1,3,0,0,9,0,0,0,0,27,1,0,0,0,0,0,0,0,0,0,

%U 21,1,3,5,8,0,15,0,0,0,0,0,40,1,0,0,0,0,0,0,0,0,0,0,0,25

%N Triangle T(n,k) = A018804(k) if k|n, else T(n,k)=0.

%C Inverse Mobius transform of a matrix with A018804 in the main diagonal and the rest zeros.

%H Reinhard Zumkeller, <a href="/A127626/b127626.txt">Rows n = 1..125 of triangle, flattened</a>

%e First few rows of the triangle are:

%e 1;

%e 1, 3;

%e 1, 0, 5;

%e 1, 3, 0, 8;

%e 1, 0, 0, 0, 9;

%e 1, 3, 5, 0, 0, 15;

%e ...

%o (Haskell)

%o a127626 n k = a127626_tabl !! (n-1) !! (k-1)

%o a127626_row n = a127626_tabl !! (n-1)

%o a127626_tabl = map

%o    (map (\x -> if x == 0 then 0 else a018804 x)) a127093_tabl

%o -- _Reinhard Zumkeller_, Jan 21 2014

%Y Cf. A051731, A038040 (row sums), A018804 (diagonal).

%Y Cf. A127093.

%K nonn,tabl,easy

%O 1,3

%A _Gary W. Adamson_, Jan 20 2007