Number of permutations of [2n] having n cycles of the form (c1, c2, ..., c_m) where c1 = min_{i>=1} c_i and c_j = min_{i>=j} c_i or c_j = max_{i>=j} c_i.
A345342
Number of permutations of [2n] having n cycles of the form (c1, c2, ..., c_m) where c1 = min_{i>=1} c_i and c_j = min_{i>=j} c_i or c_j = max_{i>=j} c_i.
Terms
- a(0) =1a(1) =1a(2) =11a(3) =195a(4) =5033a(5) =171465a(6) =7264499a(7) =368258891a(8) =21740278417
External references
- oeis: A345342