20809

Properties

Appears in sequences

• Incorrect duplicate of A297408.at n=22A007355
• Lower prime of the second gap of 2n between primes.at n=19A046789
• n consecutive primes differ by a multiple of 8 starting at a(n).at n=2A054680
• Smallest prime followed by three gaps that are multiples of 2n.at n=3A054701
• Initial prime in first sequence of n primes congruent to 1 modulo 8.at n=3A057638
• Odd prime values of sigma(k) - phi(k) taking k in increasing order.at n=46A068419
• Primes p such that the period of the decimal expansion of 1/p is a square.at n=27A072858
• Smallest prime(k) such that 2^n divides the product of composite numbers between prime(k) and prime(k+1) but 2^(n+1) does not.at n=39A077216
• Primes of the form m*rad(m)+1, where rad = A007947 (squarefree kernel).at n=44A078324
• Primes p such that (r-p)/log(p) > 4, where r is the next prime after p.at n=5A082889
• Primes of the form 8*k^2 + 1.at n=8A090685
• Primes of the form 2*n^2+1.at n=19A090698
• Primes in A051022.at n=38A092908
• Expansion of (1-x)/((1-x)^2-3x^3).at n=14A097116
• prime(k) for those k where floor((2*(prime(k+1)-prime(k))*PrimePi(k) mod (8*k))/k) = m with m = 11.at n=8A109565
• Larger of two consecutive primes whose sum is a square.at n=14A118591
• Larger member of twin prime pairs whose sum is a square.at n=8A118593
• Twin prime pairs that sum to a power.at n=21A119768
• Numbers appearing in A122072 at least four times.at n=10A122390
• Primes p such that q-p = 40, where q is the next prime after p.at n=1A126721