Largest number of the form C(n,x) + C(n,y) + C(n,z) where x + y + z = n.

Terms

a(0) =3a(1) =3a(2) =5a(3) =9a(4) =14a(5) =25a(6) =45a(7) =77a(8) =141a(9) =261a(10) =505a(11) =935a(12) =1849a(13) =3445a(14) =6865a(15) =12885a(16) =25741a(17) =48637a(18) =97241a(19) =184775a(20) =369513a(21) =705453a(22) =1410865a(23) =2704179a(24) =5408313a(25) =10400625a(26) =20801201a(27) =40116627a(28) =80233201a(29) =155117549