20647621

Appears in sequences

• Cyclotomic polynomials at x=-4.at n=21A020503
• a(n) is the least base-2 overpseudoprime k such that the multiplicative order of 2 mod k equals 8*n+20.at n=7A141629
• Numbers k (between 2^(m-1) and 2^m) such that 2^(k-1) == 1 (mod k) and 2^(k-1-m) == k - 2^p (mod k) for some p > 0 with 2^p < k.at n=37A167612