44173

Appears in sequences

• Strong pseudoprimes to base 13.at n=15A020239
• Strong pseudoprimes to base 23.at n=20A020249
• Strong pseudoprimes to base 25.at n=28A020251
• Strong pseudoprimes to base 77.at n=13A020303
• Numerators of convergents to Khinchin's constant.at n=11A127005
• A triangle sequence of the form: T(n,m) = binomial(n, m) + floor(Eulerian(n + 1, m)/2).at n=39A174035
• A triangle sequence of the form: T(n,m) = binomial(n, m) + floor(Eulerian(n + 1, m)/2).at n=41A174035
• Euler pseudoprimes to base 5: composite integers such that abs(5^((n - 1)/2)) == 1 mod n.at n=26A262052
• The "residue" pseudoprimes: odd composite numbers n such that q(n)^((n-1)/2) == 1 (mod n), where base q(n) is the smallest prime quadratic residue modulo n.at n=26A307798
• The internal state of the Sinclair ZX81 and Spectrum random number generator.at n=39A357907
• Odd numbers k > 1 such that gcd(5,k) = 1 and 5^((k-1)/2) == -(5/k) (mod k), where (5/k) is the Jacobi symbol (or Kronecker symbol); Euler pseudoprimes to base 5 (A262052) that are not Euler-Jacobi pseudoprimes to base 5 (A375914).at n=5A375816
• a(n) = Sum_{k=0..floor(n/3)} binomial(k+2,2) * binomial(k,n-3*k)^2.at n=24A377147