A192470 (A192469)/2.

1, 4, 22, 112, 589, 3100, 16393, 86800, 459994, 2438536, 12929377, 68557720, 363537265, 1927735708, 10222301758, 54206461120, 287444443765, 1524252798580, 8082769233721, 42861108613288, 227282835266626, 1205229864917272

Offset

1,2

Comments

See A192469.

Links

Table of n, a(n) for n=1..22.

Formula

Empirical G.f.: -x*(x-1)*(3*x-1)/((3*x^2+x-1)*(9*x^2-7*x+1)). [Colin Barker, Nov 12 2012]

Mathematica

(See A192468.)

Crossrefs

Cf. A192469.

Sequence in context: A077543 A084157 A085939 * A274799 A290591 A272435

Adjacent sequences: A192467 A192468 A192469 * A192471 A192472 A192473

Keyword

nonn

Author

Clark Kimberling, Jul 01 2011

Status

approved