Number of n X 3 nonnegative integer arrays each row and column an ascent sequence (interior element no greater than one plus up-steps preceding it) and the lower right element equal to min(n,3)-1.
A202730
Number of n X 3 nonnegative integer arrays each row and column an ascent sequence (interior element no greater than one plus up-steps preceding it) and the lower right element equal to min(n,3)-1.
Terms
- a(0) =1a(1) =2a(2) =2a(3) =14a(4) =78a(5) =406a(6) =2062a(7) =10374a(8) =51998a(9) =260246a(10) =1301742a(11) =6509734a(12) =32550718a(13) =162757686a(14) =813796622a(15) =4068999494a(16) =20345030238a(17) =101725216726a(18) =508626214702
External references
- oeis: A202730