22727

Properties

Appears in sequences

• Primes that contain digits 2 and 7 only.at n=8A020459
• a(n) = A078206(n) / A000422(n).at n=4A078207
• Least k such that the class number of quadratic order of discriminant D=-4k equals p, where p runs through the primes.at n=35A079029
• Primes produced by repeated application of the formula p -> (10p +- 3) starting at the prime 2.at n=15A086322
• Smallest prime p with at least two non-overlapping occurrences of n in decimal representation of p.at n=26A103611
• Square-chain primes (including square-loop primes).at n=38A108659
• Square-loop primes.at n=12A108660
• Primes in which the frequency of every digit is also prime.at n=21A113615
• Number of 4-dimensional partitions of n up to conjugacy.at n=16A119267
• Difference between two consecutive squares enclosing 3^(2n+1).at n=8A119901
• Primes with prime number of only prime digits (i.e., 2, 3, 5, 7).at n=22A124888
• Number of compositions such that the number of parts is divisible by the first part.at n=15A168655
• Primes p such that 2*p^4-+21 are also prime.at n=32A174367
• a(n) = smallest prime > a(n-1) such that a(n)+a(n-1) is multiple of k, a(1)=2, k=101.at n=34A178468
• Primes that are the average of the members of emirp pairs.at n=13A178581
• Nonpalindromic primes that are the average of the members of emirp pairs.at n=5A178585
• Primes that are the average of the members of more than one emirp pair.at n=1A178587
• Primes that are the average of the members of exactly 2 emirp pairs.at n=1A178588
• Numerator of h(n+7) - h(n), where h(n) = Sum_{k=1..n} 1/k.at n=5A192449
• G.f. satisfies A(x) = exp( Sum_{n>=1} (A(x^n) + A(-x^n))/2 * x^n/n ).at n=22A195865