Total number of ones in runs of 1s of length <=2 over all binary strings of length n.

Terms

a(0) =0a(1) =1a(2) =4a(3) =9a(4) =22a(5) =52a(6) =120a(7) =272a(8) =608a(9) =1344a(10) =2944a(11) =6400a(12) =13824a(13) =29696a(14) =63488a(15) =135168a(16) =286720a(17) =606208a(18) =1277952a(19) =2686976a(20) =5636096a(21) =11796480a(22) =24641536a(23) =51380224a(24) =106954752a(25) =222298112a(26) =461373440a(27) =956301312a(28) =1979711488a(29) =4093640704