42019

Properties

Appears in sequences

• Primes of the form n^2 - 6.at n=30A028880
• Row sums of the inverse of number triangle A(n,k) = 1/C(n) if k <= n <= 2k, 0 otherwise, where C(n) = A000108(n).at n=11A127768
• a(n) = A127768(2n+1). A bisection of the row sums of the inverse of number triangle A(n,k) = 1/C(n) if k <= n <= 2k, 0 otherwise, where C(n) = A000108(n).at n=5A127770
• Depression-type primes with five digits; from left to right digits decrease to and increase from the central digit.at n=27A157083
• Primes of form p*q + 30, where p and q are consecutive primes.at n=18A229570
• Slowest increasing sequence of primes such that a(n - 1) + a(n) and a(n - 1)^2 + a(n)^2 are both semiprimes, with a(1)=2.at n=29A365050
• a(n) is the smallest prime p such that p - a(n-1) is a primorial, starting with a(1)=2.at n=13A380026
• Prime numbersat n=4395