1969417

Appears in sequences

• Sarrus numbers (A001567) that are the average of two consecutive primes.at n=20A265684
• Numbers k such that 2^(k-1) == 1 (mod k) and p-1 does not divide k-1 for every prime p dividing k.at n=33A316907
• Base-2 Fermat pseudoprimes k such that the multiplicative order of 2 modulo k is odd.at n=17A367230
• Composite numbers k such that 2^(2^(k-1)-1) == 1 (mod k^2).at n=9A376253