Number of unimodal functions [1..n]->[1..n].

Terms

a(0) =1a(1) =4a(2) =22a(3) =130a(4) =791a(5) =4900a(6) =30738a(7) =194634a(8) =1241383a(9) =7963384a(10) =51325352a(11) =332095816a(12) =2155894508a(13) =14035149748a(14) =91593941402a(15) =599021799242