Number of ways to toss a coin n times and not get a run of five.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =16a(5) =30a(6) =58a(7) =112a(8) =216a(9) =416a(10) =802a(11) =1546a(12) =2980a(13) =5744a(14) =11072a(15) =21342a(16) =41138a(17) =79296a(18) =152848a(19) =294624a(20) =567906a(21) =1094674a(22) =2110052a(23) =4067256a(24) =7839888a(25) =15111870a(26) =29129066a(27) =56148080a(28) =108228904a(29) =208617920