Number of rules of a context-free grammar in Chomsky normal form that generates all permutations of n symbols.

A090328

Number of rules of a context-free grammar in Chomsky normal form that generates all permutations of n symbols.

Terms

    a(0) =1a(1) =4a(2) =12a(3) =35a(4) =103a(5) =306a(6) =914a(7) =2737a(8) =8205a(9) =24608a(10) =73816a(11) =221439a(12) =664307a(13) =1992910a(14) =5978718a(15) =17936141a(16) =53808409a(17) =161425212a(18) =484275620a(19) =1452826843a(20) =4358480511a(21) =13075441514a(22) =39226324522a(23) =117678973545a(24) =353036920613

External references