52631

Properties

Appears in sequences

• a(n) = floor(10^6/n).at n=18A033426
• Primes arising in A090517, or 0 if A090517(n) = 0.at n=5A090518
• Primes arising in A090519, or 0 if A090519(n)= 0.at n=5A090520
• Primes of the form (k+1)*prime(k) + k*prime(k+1).at n=27A097241
• Primes with a twin Carmichael number: primes p such that p-2 or p+2 are Carmichael numbers.at n=7A135437
• Primes p of the form A152539(n) + 1.at n=36A152540
• Number of nondecreasing integer sequences of length 22 with sum zero and sum of absolute values 2n.at n=15A158156
• Least prime k such that x' = k has n solutions, where x' is the arithmetic derivative (A003415) of x.at n=36A189559
• Least odd number k such that x' = k has n solutions, where x' is the arithmetic derivative (A003415) of x.at n=36A189560
• Lesser of pseudo twin primes to base 2.at n=29A192297
• Numbers k such that at least one of k and k+2 is composite, while for every b coprime to k*(k+2), b^(k-1) == 1 (mod k) and b^(k+1) == 1 (mod k+2).at n=7A194231
• Fibonacci + Goldbach (dual sequence to A216275). a(1)=5, a(2)=7 and for n>=3, a(n) = g(a(n-1) + a(n-2)), where for m>=3, g(2*m) is the maximal prime p < 2*m such that 2*m - p is prime.at n=22A216835
• Primes formed by the initial digits of the decimal expansion of 1/19, starting at the first nonzero digit in the expansion.at n=1A242833
• Primes p such that p + 2 is a Carmichael number (A002997).at n=5A272754
• Primes that can be generated by the concatenation in base 7, in descending order, of two consecutive integers read in base 10.at n=33A287309
• Number of 7-element subsets of [n] having a prime element sum.at n=16A320682
• The number of vertices inside a cross with width 3 and height n (see Comments in A331455 for definition) formed by the straight line segments mutually connecting all vertices and all points.at n=23A330850
• a(n) is the least number that can be written in exactly n ways as p*q + q*r + p*r where (p,q,r) is an unordered triple of distinct primes.at n=36A356457
• a(n) is the first prime p such that the average of the n-th powers of n consecutive primes starting with p is prime.at n=22A359323
• Prime numbersat n=5374