a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 5, with initial values 1,1,2,1.
A025271
a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 5, with initial values 1,1,2,1.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =1a(4) =6a(5) =18a(6) =52a(7) =165a(8) =518a(9) =1646a(10) =5308a(11) =17258a(12) =56604a(13) =187108a(14) =622632a(15) =2084461a(16) =7016134a(17) =23730006a(18) =80610156a(19) =274911614a(20) =940915892a(21) =3230919164a(22) =11127525464a(23) =38429281122a(24) =133052559772a(25) =461740643276
External references
- oeis: A025271