20507

Properties

Appears in sequences

• Primes that remain prime through 3 iterations of function f(x) = 6x + 7.at n=16A023289
• Numbers k such that 71*2^k+1 is prime.at n=21A032385
• Luhn primes: primes p such that p + (p reversed) is also a prime.at n=42A061783
• a(1) = 2, a(n+1) is the smallest prime greater than n*a(n).at n=7A077213
• Smallest member of a pair of consecutive twin prime pairs that have three primes between them.at n=27A089635
• Primes in A051022.at n=34A092908
• Primes p such that p + 2 and p^2 + 2^2 are primes.at n=34A107312
• Prime numbers obtained by inserting a 0 between each pair of adjacent digits of a prime number > 10.at n=24A119680
• Primes p such that p - q = 24, where q is the previous prime before p; or prime numbers preceded by precisely 23 composite numbers.at n=34A126720
• Primes congruent to 34 mod 59.at n=38A142761
• Prime numbers where the last digit is the sum of all the previous digits.at n=30A156617
• Primes of the form m*(m+1)/2 + 4.at n=34A159048
• Chen primes A109611(k) which have the same sum-of-digits as their index k.at n=39A176012
• Primes that are the average of the members of emirp pairs.at n=8A178581
• Nonpalindromic primes that are the average of the members of emirp pairs.at n=0A178585
• Number of partitions of n with no part equal to 1 or 3.at n=54A181531
• Least n-gap prime: a(n) = least prime p for which there is no prime between n*p and n*q, where q is the next prime after p.at n=23A195325
• Records of A195325.at n=10A195329
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 481", based on the 5-celled von Neumann neighborhood.at n=29A272457
• Prime time primes (of the form HMMSS with primes H < 24 and MM, SS < 60) such that the corresponding number of seconds after midnight is also prime.at n=3A295000