66977792

Appears in sequences

• Number of subsets of {1,..,n} containing at least one prime.at n=25A089820
• Numbers whose binary representation is the concatenation of n 1's and 2n-1 digits 0.at n=8A147538
• Expansion of 1/((1-4*x^2)^(3/2)-2*x*(1-4*x^2)).at n=17A270822
• a(n) = 2^n - 2^floor(2n/3).at n=26A291779