A181653 Generalized (conditional) Riordan array with k-th column generated by x^k*(1+x) if k mod 2 = 0, x^k*(1+x+x^2) otherwise.

1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1

Offset: 0

Author

Paul Barry, Nov 03 2010

Keywords

• easy
• nonn
• tabl

Comments

Row sums are A174296. A181654 is an eigentriangle.

Examples

			Triangle begins
  1;
  1, 1;
  0, 1, 1;
  0, 1, 1, 1;
  0, 0, 0, 1, 1;
  0, 0, 0, 1, 1, 1;
  0, 0, 0, 0, 0, 1, 1;
  0, 0, 0, 0, 0, 1, 1, 1;
  0, 0, 0, 0, 0, 0, 0, 1, 1;
  0, 0, 0, 0, 0, 0, 0, 1, 1, 1;
  0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1;
Production matrix begins
   1,  1;
  -1,  0,  1;
   1,  1,  0,  1;
   0, -1, -1,  0,  1;
   0,  1,  1,  1,  0,  1;
   0,  0,  0, -1, -1,  0,  1;
   0,  0,  0,  1,  1,  1,  0,  1;
   0,  0,  0,  0,  0, -1, -1,  0,  1;
   0,  0,  0,  0,  0,  1,  1,  1,  0,  1;
   0,  0,  0,  0,  0,  0,  0, -1, -1,  0,  1;