Number of inequivalent ways to select n cards in the game of SET.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =15a(7) =34a(8) =105a(9) =384a(10) =1658a(11) =8135a(12) =41407a(13) =205211a(14) =963708a(15) =4231059a(16) =17295730a(17) =65807588a(18) =233346408a(19) =772518828a(20) =2392611091a(21) =6946116261a(22) =18937468347a(23) =48568206996