A168151 Riordan array (1/u,(1-u)/2), u=sqrt(1-4x+4*x^3).

1, 2, 1, 6, 3, 1, 18, 9, 4, 1, 58, 29, 13, 5, 1, 192, 96, 44, 18, 6, 1, 650, 325, 151, 64, 24, 7, 1, 2232, 1116, 524, 228, 90, 31, 8, 1, 7746, 3873, 1833, 813, 333, 123, 39, 9, 1, 27096, 13548, 6452, 2904, 1222, 473, 164, 48, 10, 1

Offset: 0

Author

Philippe Deléham, Nov 19 2009

Keywords

• nonn
• tabl

Comments

T(n,0) = A157004(n).

Examples

			Triangle begins:
  1
  2 1
  6 3 1
  18 9 4 1
  58 29 13 5 1
  192 96 44 18 6 1
  650 325 151 64 24 7 1
  ...
		

References

• Baccherini, D.; Merlini, D.; Sprugnoli, R. Binary words excluding a pattern and proper Riordan arrays. Discrete Math. 307 (2007), no. 9-10, 1021--1037. MR2292531 (2008a:05003). See Example 5.6. - N. J. A. Sloane, Mar 25 2014

Crossrefs

Cf. A025262, A157004.

Formula

T(n,0) = 2*T(n,1) for n>0, T(0,0) = 1, T(n,k) = T(n-1,k-1)-T(n-3,k-1)+T(n,k+1).