a(n) = 2^n - C(n,0) - ... - C(n,4).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =1a(6) =7a(7) =29a(8) =93a(9) =256a(10) =638a(11) =1486a(12) =3302a(13) =7099a(14) =14913a(15) =30827a(16) =63019a(17) =127858a(18) =258096a(19) =519252a(20) =1042380a(21) =2089605a(22) =4185195a(23) =8377705a(24) =16764265a(25) =33539156a(26) =67090962a(27) =134196874a(28) =268411298a(29) =536843071