A134635 Row sums of triangle A134634.

1, 2, 6, 18, 54, 164, 508, 1610, 5222, 17308, 58484, 200948, 700348, 2470472, 8804024, 31648858, 114623366, 417820972, 1531629764, 5642508508, 20878731476, 77561756152, 289156105544, 1081466311108, 4056621689564, 15257327887384, 57525469116168, 217383333920040, 823195469508792, 3123379468819600, 11872247508521072, 45203794091311354

Offset: 0

Author

Gary W. Adamson, Nov 04 2007

Keywords

• nonn

Examples

			a(3) = 18 = sum of row 3 terms of triangle A134634: (5 + 4 + 4 + 5).
		

Links

• Noah Arbesfeld, Partial permutations avoiding pairs of patterns, Discrete Math., 313 (2013), 2614-2625.

Crossrefs

Cf. A000108, A126966, A134634.

Programs

Maple

A134635 := n -> 2*binomial(2*n, n)/(n+1) + add(2^k*binomial(2*n-2*k, n-k)/(2*n-2*k-1), k=0..n): seq(A134635(n), n=0..31); # Mélika Tebni, Feb 11 2024

Formula

Conjecture: (n+1)*a(n) +(-7*n+1)*a(n-1) +2*(7*n-8)*a(n-2) +4*(-2*n+5)*a(n-3)=0. - R. J. Mathar, May 30 2014

a(n) = 2*A000108(n) - A126966(n). - Mélika Tebni, Feb 11 2024

Extensions

Corrected and extended by N. J. A. Sloane, Feb 18 2013