80581

Appears in sequences

• Strong pseudoprimes to base 2.at n=12A001262
• Strong pseudoprimes to base 4.at n=26A020230
• Strong pseudoprimes to base 8.at n=36A020234
• Cyclotomic polynomials at x=-4.at n=15A020503
• Euler-Jacobi pseudoprimes: 2^((n-1)/2) == (2 / n) mod n, where (2 / n) is a Jacobi symbol.at n=31A047713
• Super-Poulet numbers: Poulet numbers whose divisors d all satisfy d|2^d-2.at n=29A050217
• a(n) = n^8 + n^7 - n^5 - n^4 - n^3 + n + 1.at n=4A060894
• a(n) = (lcm_{k=0..n} (2^k + 1))/(lcm_{k=0..n-1} (2^k + 1)).at n=29A066845
• a(n) is the maximal overpseudoprime q to base 2 such that the multiplicative order of 2 mod q equals A143584(n).at n=23A131952
• Overpseudoprimes to base 2: composite k such that k = A137576((k-1)/2).at n=5A141232
• a(n) is the least base-2 overpseudoprime k such that the multiplicative order of 2 mod k equals 8*n+20.at n=4A141629
• Numbers representable as Phi(k,2), the k-th cyclotomic polynomial evaluated at 2, for some k>0.at n=29A153601
• 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=18A167612
• Increasing gaps between 2-pseudoprimes (upper end).at n=12A175737
• Fermat pseudoprimes to base 2 with two prime factors.at n=29A214305
• Composite numbers k congruent to 5 (mod 8) such that 2^((k-1)/2) mod k = k-1.at n=3A244626
• Composite numbers k == 1 (mod 4) such that (1 + i)^k == 1 + i (mod k), where i = sqrt(-1).at n=29A270698
• Plumb pseudoprimes: odd composites that pass Colin Plumb's extended Euler criterion test.at n=24A288153
• Composite integers k such that 2^d == 2^(k/d) (mod k) for all d|k.at n=32A291601
• Numbers p_1*p_2*...*p_k such that (2^p_1-1)*(2^p_2-1)*...*(2^p_k-1) is a Poulet number (A001567), where p_i are primes and k >= 2.at n=32A291617