Number of subsets of {1,2,...,n-8} without differences equal to 4 or 8.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =1a(9) =2a(10) =4a(11) =8a(12) =16a(13) =24a(14) =36a(15) =54a(16) =81a(17) =108a(18) =144a(19) =192a(20) =256a(21) =384a(22) =576a(23) =864a(24) =1296a(25) =1944a(26) =2916a(27) =4374a(28) =6561a(29) =9477