a(n) = (1/4)*A291024(n).

Terms

a(0) =0a(1) =1a(2) =2a(3) =6a(4) =16a(5) =43a(6) =114a(7) =300a(8) =784a(9) =2037a(10) =5266a(11) =13554a(12) =34752a(13) =88799a(14) =226210a(15) =574680a(16) =1456352a(17) =3682409a(18) =9292002a(19) =23403102a(20) =58842416a(21) =147713043a(22) =370262930a(23) =926852868a(24) =2317191024a(25) =5786293597a(26) =14433117938a(27) =35964267594a(28) =89528469088a(29) =222666575815