Number of bitriangular permutations (row sums of A272644 if that triangle is prefixed with two rows for n=0,1).

A297195

Number of bitriangular permutations (row sums of A272644 if that triangle is prefixed with two rows for n=0,1).

Terms

    a(0) =1a(1) =0a(2) =1a(3) =2a(4) =7a(5) =28a(6) =133a(7) =726a(8) =4483a(9) =30896a(10) =235105a(11) =1957930a(12) =17712799a(13) =172980804a(14) =1813760317a(15) =20323234814a(16) =242353047355

External references