Number of weighted voting procedures.

Terms

a(0) =1a(1) =3a(2) =9a(3) =21a(4) =51a(5) =117a(6) =271a(7) =607a(8) =1363a(9) =3013a(10) =6643a(11) =14491a(12) =31495a(13) =67965a(14) =146115a(15) =312483a(16) =666015a(17) =1413915a(18) =2992815a(19) =6315135a(20) =13292007a(21) =27906585a(22) =58464339a(23) =122229123a(24) =255072423a(25) =531369483a(26) =1105217223a(27) =2295383319a(28) =4760727375