A130266 - OEIS

%I #6 Feb 20 2022 14:45:25

%S 1,1,2,4,1,3,2,5,1,4,7,2,6,1,5,3,8,2,7,1,6,10,3,9,2,8,1,7,4,11,3,10,2,

%T 9,1,8,13,4,12,3,11,2,10,1,9,5,14,4,13,3,12,2,11,1,10,16,5,15,4,14,3,

%U 13,2,12,1,11,6,17,5,16,4,15,3,14,2,13

%N A051340 * A128174.

%C Row sums = A014255: (1, 3, 8, 12, 21, 27, 40, ...).

%C Left border = A123684: (1, 1, 4, 2, 7, 3, 10, 4, ...).

%F A051340 * A128174 as infinite lower triangular matrices.

%e First few rows of the triangle:

%e    1;

%e    1, 2;

%e    4, 1, 3;

%e    2, 5, 1, 4;

%e    7, 2, 6, 1, 5;

%e    3, 8, 2, 7, 1, 6;

%e   10, 3, 9, 2, 8, 1, 7;

%e   ...

%p A128174 := proc(n,k)

%p     if k > n or k < 1 then

%p         0;

%p     else

%p         modp(k+n+1,2) ;

%p     end if;

%p end proc:

%p A051340 := proc(n,k)

%p     if k = n then

%p         n ;

%p     elif k <= n then

%p         1;

%p     else

%p         0;

%p     end if;

%p end proc:

%p A130266 := proc(n,k)

%p     add( A051340(n,j)*A128174(j,k),j=k..n) ;

%p end proc:

%p seq(seq(A130266(n,k),k=1..n),n=1..15) ; # _R. J. Mathar_, Aug 06 2016

%Y Cf. A051340, A128174, A014255, A123684.

%K nonn,tabl,easy

%O 0,3

%A _Gary W. Adamson_, May 18 2007