Number of binary vectors of length n containing no singletons.

Terms

a(0) =1a(1) =0a(2) =2a(3) =2a(4) =4a(5) =6a(6) =10a(7) =16a(8) =26a(9) =42a(10) =68a(11) =110a(12) =178a(13) =288a(14) =466a(15) =754a(16) =1220a(17) =1974a(18) =3194a(19) =5168a(20) =8362a(21) =13530a(22) =21892a(23) =35422a(24) =57314a(25) =92736a(26) =150050a(27) =242786a(28) =392836a(29) =635622