A181656 - OEIS

%I #5 Sep 29 2018 18:47:32

%S 1,0,1,1,1,1,0,0,0,1,0,0,1,1,1,0,0,0,0,0,1,0,0,0,0,1,1,1,0,0,0,0,0,0,

%T 0,1,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,1,1

%N Generalized (conditional) Riordan array with k-th column generated by x^k*(1+x^2) if k mod 2 = 0, x^k*(1+x) otherwise.

%C A181657 is an eigentriangle for this triangle.

%e Triangle begins

%e   1;

%e   0, 1;

%e   1, 1, 1;

%e   0, 0, 0, 1;

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

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

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

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

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

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

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

%e Production matrix begins

%e    0,  1;

%e    1,  1,  1;

%e   -1, -2, -1,  1;

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

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

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

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

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

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

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

%K easy,nonn,tabl

%O 0,1

%A _Paul Barry_, Nov 03 2010