A143151 - OEIS

%I #5 Nov 12 2021 12:24:19

%S 1,1,2,1,0,3,1,2,0,2,1,0,0,0,5,1,2,3,0,0,2,1,0,0,0,0,0,7,1,2,0,2,0,0,

%T 0,2,1,0,3,0,0,0,0,0,3,1,2,0,0,5,0,0,0,0,2,1,0,0,0,0,0,0,0,0,0,11,1,2,

%U 3,2,0,2,0,0,0,0,0,2,1,0,0,0,0,0,0,0,0,0,0,0,13,1,2,0,0,0,0,7,0,0,0,0,0,0,2

%N Triangle read by rows, A051731 * (A020639 * 0^(n-k)), 1<=k<=n.

%C Row sums = A143152: (1, 3, 4, 5, 6, 8, 8, 7, 7, 10, 12, 12, 14, 12,

%F Triangle read by rows, A051731 * (A020639 * 0^(n-k)), 1<=k<=n; where A020639 = Lpf(n). By rows, least prime factors of the divisors of n, where the divisors of n are recorded in triangle A127093.

%e First few rows of the triangle are:

%e   1;

%e   1, 2;

%e   1, 0, 3;

%e   1, 2, 0, 2;

%e   1, 0, 0, 0, 5;

%e   1, 2, 3, 0, 0, 2;

%e   1, 0, 0, 0, 0, 0, 7;

%e   1, 2, 0, 2, 0, 0, 0, 2;

%e   1, 0, 3, 0, 0, 0, 0, 0, 3;

%e   1, 2, 0, 0, 5, 0, 0, 0, 0, 2;

%e   1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11;

%e   ...

%e Row 12 = (1, 2, 3, 2, 0, 2, 0, 0, 0, 0, 0, 2) since the divisors of 12 are shown in row 12 of triangle A127093: (1, 2, 3, 4, 0, 6, 0, 0, 0, 0, 0, 12).

%e Lpf of these terms = row 12 of A143152.

%Y Cf. A020639, A127093, A143152.

%K nonn,tabl

%O 1,3

%A Gary W. Adamson & _Mats Granvik_, Jul 27 2008