721392

Appears in sequences

• Number of "bifix-free" words of length n over a four-letter alphabet.at n=10A019309
• A019309(n)/4 for n >= 1.at n=10A094547
• a(1) = 6; for n>1, a(n) = prime(n)*(prime(n)^2 - 1)/2.at n=29A117762
• Half of product of three numbers: n-th prime, previous and following number.at n=29A127918
• Primitive non-solvable numbers: orders of non-solvable groups such that all groups with order a proper divisor of that order are solvable.at n=20A216480