Number of irreducible permutations of n with partition type [2, 1, 1, ..., 1] (with '1' taken n - 2 times).

A356114

Number of irreducible permutations of n with partition type [2, 1, 1, ..., 1] (with '1' taken n - 2 times).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =2a(4) =9a(5) =24a(6) =55a(7) =118a(8) =245a(9) =500a(10) =1011a(11) =2034a(12) =4081a(13) =8176a(14) =16367a(15) =32750a(16) =65517a(17) =131052a(18) =262123a(19) =524266a(20) =1048553a(21) =2097128a(22) =4194279a(23) =8388582a(24) =16777189a(25) =33554404a(26) =67108835a(27) =134217698a(28) =268435425a(29) =536870880

External references