Coefficient of x^(2*n) in the expansion of (1 + x^3 + x^4)^n.

Terms

a(0) =1a(1) =0a(2) =2a(3) =3a(4) =6a(5) =30a(6) =35a(7) =210a(8) =350a(9) =1344a(10) =3402a(11) =9240a(12) =29139a(13) =72072a(14) =231660a(15) =603603a(16) =1814670a(17) =5095376a(18) =14507324a(19) =42401502a(20) =118974466a(21) =349305120a(22) =990073812a(23) =2877816304a(24) =8272748675a(25) =23852438880a(26) =69116072950a(27) =198980348385a(28) =577566713520