Number of standard Young tableaux with n cells and 4 as last value in the first row.

Terms

a(0) =4a(1) =7a(2) =14a(3) =29a(4) =66a(5) =152a(6) =374a(7) =933a(8) =2440a(9) =6476a(10) =17812a(11) =49700a(12) =142806a(13) =416028a(14) =1244052a(15) =3769709a(16) =11701968a(17) =36779876a(18) =118196856a(19) =384069992a(20) =1272985450a(21) =4258319604a(22) =14489712986a(23) =49658295960a(24) =172626616246a(25) =603254904952