22129

Properties

Appears in sequences

• 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 19.at n=6A031607
• Primes with 19 as smallest positive primitive root.at n=20A061331
• Primes arising in A073946.at n=14A113943
• Primes p such that for the cyclic group Zp of a prime order p there exist a perfect 4-shift code {+-1,+-a,+-a^2,+-b} in Zp.at n=20A162542
• a(n) = A005291(n) + A005291(n+1).at n=34A195308
• Numbers n such that n!10 + 2 is prime.at n=47A204657
• Primes formed by concatenation (exponent then prime) of prime factorizations of the positive integers.at n=25A226095
• Primes p = prime(n): such that p.n and n.p both are prime, where (.) indicates concatenation.at n=32A243886
• Let F(g,p) be the frequency of g up to prime nextprime(p+1). Primes p such that F(2,p) = F(4,p) and g = 2 or 4.at n=46A274122
• Prime numbers congruent to 49 or 121 modulo 240 representable by x^2 + 150*y^2.at n=38A325089
• a(0) = a(1) = a(2) = 1; a(n) = Sum_{k=1..n-3} a(k) * a(n-k-3).at n=26A346047
• Prime numbersat n=2481