Number of productions of a certain "divide-and-conquer" context-free grammar in Chomsky normal form that generates all permutations of n symbols.

A092285

Number of productions of a certain "divide-and-conquer" context-free grammar in Chomsky normal form that generates all permutations of n symbols.

Terms

    a(0) =1a(1) =4a(2) =12a(3) =22a(4) =65a(5) =116a(6) =399a(7) =554a(8) =2475a(9) =3232a(10) =14938a(11) =20208a(12) =101413a(13) =130846a(14) =691890a(15) =924946a(16) =4867559a(17) =6281552a(18) =35154066a(19) =46902128a(20) =253485141a(21) =328375720a(22) =1877693458a(23) =2504042868a(24) =13754442225a(25) =17885555976a(26) =103317302754a(27) =137761862662a(28) =765705075439a(29) =998817493980

External references