A342906 a(n) = 2^(2*n-2) - Catalan(n).

0, 2, 11, 50, 214, 892, 3667, 14954, 60674, 245348, 989790, 3986292, 16034316, 64434424, 258740611, 1038384154, 4165322506, 16702230484, 66952213546, 268313786524, 1075045360756, 4306563947464, 17249126430766, 69078840030340, 276613030309204, 1107532553770472, 4434066076454492

Offset

1,2

Comments

Since Catalan(n) enumerates so many different things, natural upper bounds like this and A006516 are candidates for counting objects not having some property.

Links

Table of n, a(n) for n=1..27.

Prog

(Python)
from sympy import catalan
def A342906(n): return 2**(2*n-2)-catalan(n) # Chai Wah Wu, Apr 01 2021

Crossrefs

Cf. A000108, A006516.

Sequence in context: A262296 A151314 A316263 * A187000 A154415 A108851

Adjacent sequences: A342903 A342904 A342905 * A342907 A342908 A342909

Keyword

nonn

Author

N. J. A. Sloane, Mar 31 2021

Status

approved