The number of ways one can flip seven consecutive tails (or heads) when flipping a coin n times.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =1a(8) =3a(9) =8a(10) =20a(11) =48a(12) =112a(13) =256a(14) =576a(15) =1279a(16) =2811a(17) =6126a(18) =13256a(19) =28512a(20) =61008a(21) =129952a(22) =275712a(23) =582913a(24) =1228551a(25) =2582048a(26) =5412984a(27) =11321744a(28) =23631056a(29) =49229312