7381975040domain: NAppears in sequencesExpansion of g.f. (1+2*x)/(1-2*x)^2.at n=27A0144808th binomial transform of (0,0,1,0,0,0, ...).at n=11A081138a(n) = 2^(n-1)*A047240(n).at n=28A128205Number of runs of 1's of length <= 3 over all binary strings of length n.at n=30A386878