a(n) = Sum_{k=0..floor(5*n/14)} binomial(k,5*n-14*k).

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =0a(5) =0a(6) =1a(7) =0a(8) =0a(9) =1a(10) =0a(11) =0a(12) =1a(13) =0a(14) =1a(15) =1a(16) =0a(17) =6a(18) =1a(19) =0a(20) =21a(21) =1a(22) =0a(23) =56a(24) =1a(25) =0a(26) =126a(27) =1a(28) =1a(29) =252