A047036 T(n,n+1), array T as in A047030.

1, 2, 6, 20, 69, 246, 896, 3312, 12371, 46582, 176528, 672464, 2572700, 9878116, 38044450, 146911680, 568617615, 2205268306, 8567986878, 33341710740, 129932332749, 506997589626, 1980621229040, 7745660095820, 30320567651424

Offset

0,2

Comments

If Y is a fixed 4-subset of a 2n-set X then a(n) is the number of n-subsets of X intersecting Y - Milan Janjic, Oct 21 2007

Links

Table of n, a(n) for n=0..24.

Milan Janjic, Two Enumerative Functions

Crossrefs

Sequence in context: A163135 A359463 A331951 * A199248 A148478 A148479

Adjacent sequences: A047033 A047034 A047035 * A047037 A047038 A047039

Keyword

nonn

Author

Clark Kimberling

Status

approved