1325843

Appears in sequences

• Overpseudoprimes to base 2: composite k such that k = A137576((k-1)/2).at n=31A141232
• Pseudoprimes to base 2 of the form 4k+3.at n=38A177884
• Composite numbers m such that (4^m - 2^m + 8*m^2 - 2) / (2*m*(2*m + 1)) is an integer.at n=16A235540
• Composite numbers n such that n == 3 (mod 8) and 2^((n-1)/2) == -1 (mod n).at n=3A244628
• Composite numbers k == 3 (mod 4) such that (1 + i)^k == 1 - i (mod k), where i = sqrt(-1).at n=11A270697
• The "non-residue" pseudoprimes: odd composite numbers n such that b(n)^((n-1)/2) == -1 (mod n), where base b(n) = A020649(n).at n=25A307767
• Numbers k such that 2^(k-1) == 1 (mod k) and lpf(k)-1 does not divide k-1.at n=31A316906
• 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=28A316907
• Lucasian pseudoprimes: composite numbers k such that 2^(k-1) == k+1 (mod k(2k+1)).at n=2A343679
• Odd composite numbers k such that 2^((k-1)/2) == -1 (mod k).at n=18A356638