168330

Appears in sequences

• Number of 4-block ordered bicoverings of an unlabeled n-set.at n=26A060091
• a(n) = [x^n] ( 1 + x*A(x)^(n+1) )^(n+1) / (n+1) for n>=0, with a(0)=1.at n=6A242795
• Number of odd squarefree semiprimes < 10^n.at n=5A292785