47861

Appears in sequences

• a(0) = 0, a(1) = 1 and for n >= 2, a(n) = floor(2 * sqrt(a(n-2) * a(n-1))).at n=26A093333
• a(n) is the sum of the terms of the symmetric square array defined by M(i,j) = prime(i)+i-j for i >= j and M(i,j) = M(j,i) if i < j.at n=25A308731
• Number of nonempty subsets of {1..n} whose elements have an odd root mean square.at n=24A357415