233097

Appears in sequences

• First of three consecutive Sophie Germain semiprimes: n, n+1 and n+2 are all terms of A111153.at n=8A283527
• a(n)/A163403(n) = the total length of the lines drawn at generation n for Conant's dissection of a square with size 1.at n=19A337780
• Semiprimes k such that k+1, k+2, 2*k+1 and 2*k+3 are also semiprimes.at n=21A362200