Number of compositions of n such that the first part is 1 and the second differences of the parts are in {-1,0,1}.
A239551
Number of compositions of n such that the first part is 1 and the second differences of the parts are in {-1,0,1}.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =4a(6) =6a(7) =9a(8) =13a(9) =18a(10) =24a(11) =34a(12) =49a(13) =71a(14) =100a(15) =145a(16) =205a(17) =295a(18) =423a(19) =610a(20) =872a(21) =1260a(22) =1804a(23) =2599a(24) =3733a(25) =5381a(26) =7725a(27) =11131a(28) =15996a(29) =23042
External references
- oeis: A239551