4165647domain: NAppears in sequencesa(0)=0, a(1)=1, a(2)=2; for n > 2, a(n) = 3*a(n-1) - a(n-2) - 2*a(n-3).at n=22A027934Number of compositions of n with at least 1 odd and 1 even part.at n=22A097895Dirichlet convolution of A011782 (2^(n-1)) with A349451 (Dirichlet inverse of Fibonacci numbers).at n=22A349566