A046222 First numerator and then denominator of central elements of 1/2-Pascal triangle.

1, 1, 1, 2, 3, 1, 11, 1, 40, 1, 147, 1, 546, 1, 2046, 1, 7722, 1, 29315, 1, 111826, 1, 428298, 1, 1646008, 1, 6344366, 1, 24515700, 1, 94942620, 1, 368404110, 1, 1431985635, 1, 5574725970, 1, 21732560850, 1, 84828633120, 1, 331488081210, 1

Offset

1,4

Links

Table of n, a(n) for n=1..44.

Example

1/1; 1/1 1/1; 1/1 1/2 1/1; 1/1 3/2 3/2 1/1; 1/1 5/2 3/1 5/2 1/1; 1/1 7/2 11/2 11/2 7/2 1/1; 1/1 9/2 9/1 11/1 9/1 9/2 1/1; 1/1 11/2 27/2 20/1 20/1 27/2 11/2 1/1; ...

Crossrefs

Cf. A046213.

Sequence in context: A211019 A298401 A009026 * A291647 A074307 A163486

Adjacent sequences: A046219 A046220 A046221 * A046223 A046224 A046225

Keyword

nonn

Author

Mohammad K. Azarian

Extensions

More terms from James A. Sellers, Dec 13 1999

Status

approved