2134277

Appears in sequences

• Sarrus numbers k such that k-1 and k+1 have the same number of prime divisors (counted with multiplicity).at n=18A086806
• Brilliant Sarrus numbers.at n=26A086837
• Fermat pseudoprimes to base 2 that are pentagonal.at n=5A293623
• Numbers k > 1 such that 2^k == 2 (mod k) and gcd(k, 3^k - 3) = 1.at n=24A300762
• a(n) is the smallest k such that the p-rank of (Z/kZ)* is 2, where p = prime(n) and (Z/kZ)* is the multiplicative group of integers modulo n.at n=34A307434
• Fermat pseudoprimes to base 2 (A001567) k such that A003961(k) is also a Fermat pseudoprime to base 2.at n=3A346568