a(n) = floor(n!*(3*floor(n/2)!*ceiling(n/2)! + 3*floor((n+2)/2)!*ceiling((n-2)/2)! - 6*floor(n/2)!*ceiling((n-2)/2)!)^(-1)).

A366109

a(n) = floor(n!*(3*floor(n/2)!*ceiling(n/2)! + 3*floor((n+2)/2)!*ceiling((n-2)/2)! - 6*floor(n/2)!*ceiling((n-2)/2)!)^(-1)).

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =13a(6) =26a(7) =46a(8) =92a(9) =168a(10) =333a(11) =616a(12) =1225a(13) =2288a(14) =4558a(15) =8580a(16) =17107a(17) =32413a(18) =64664a(19) =123170a(20) =245832a(21) =470288a(22) =938943a(23) =1802770a(24) =3600207a(25) =6933733a(26) =13849778a(27) =26744400a(28) =53429368a(29) =103411680

External references