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

0,2

Links

Table of n, a(n) for n=0..31.

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

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

Example

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

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

Crossrefs

Cf. A000108, A126966, A134634.

Sequence in context: A179362 A008776 A025192 * A192338 A114464 A007206

Adjacent sequences: A134632 A134633 A134634 * A134636 A134637 A134638

Keyword

nonn

Author

Gary W. Adamson, Nov 04 2007

Extensions

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

Status

approved