85489

Appears in sequences

• Strong pseudoprimes to base 2.at n=13A001262
• Composite numbers k such that k == +-1 (mod 8) and 2^((k-1)/2) == 1 (mod k).at n=28A006971
• Numbers n such that game of n X n Button Madness need have no solution; this lists only the primitive elements of the set.at n=17A007802
• Strong pseudoprimes to base 4.at n=28A020230
• Strong pseudoprimes to base 8.at n=37A020234
• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 38.at n=10A031626
• Euler-Jacobi pseudoprimes: 2^((n-1)/2) == (2 / n) mod n, where (2 / n) is a Jacobi symbol.at n=32A047713
• a(n) = T(4,n), array T given by A048505.at n=10A048509
• Super-Poulet numbers: Poulet numbers whose divisors d all satisfy d|2^d-2.at n=31A050217
• Numbers n such that F_n(x) and F_n(1-x) have a common factor mod 2, with F_n(x) = U(n-1,x/2) the monic Chebyshev polynomials of second kind; this lists only the primitive elements of the set.at n=24A094425
• Pseudotwinprimes p+2 for primes p such that p+2 divides p^(p+2)+2 and p+2 is composite.at n=27A100873
• Overpseudoprimes to base 2: composite k such that k = A137576((k-1)/2).at n=6A141232
• 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=19A167612
• Fermat pseudoprimes to base 2 of the form (6*k - 1)*((6*k - 2)*n + 1), where k and n are positive integers.at n=39A210993
• Fermat pseudoprimes to base 2 with two prime factors.at n=31A214305
• Fermat pseudoprimes to base 2 of the form m*n^2 + (11*m - 23)*n + 19*m - 49, where m, n >= 0.at n=31A215326
• Fermat pseudoprimes to base 2 which are congruent to 1 (mod 8).at n=37A218483
• Strong pseudoprimes (base 2) that become prime when two is subtracted.at n=5A230483
• Strong pseudoprimes k to base 2 such that either k-2 or k+2 is prime.at n=5A230487
• Composite numbers k == 1 (mod 4) such that (1 + i)^k == 1 + i (mod k), where i = sqrt(-1).at n=30A270698