Number of compositions of n such that the difference between adjacent parts is at least two.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =4a(6) =6a(7) =9a(8) =15a(9) =23a(10) =36a(11) =55a(12) =87a(13) =136a(14) =212a(15) =329a(16) =515a(17) =802a(18) =1251a(19) =1949a(20) =3043a(21) =4745a(22) =7401a(23) =11535a(24) =17994a(25) =28063a(26) =43766a(27) =68243a(28) =106433a(29) =165981