27827

Properties

Appears in sequences

• Primes that remain prime through 4 iterations of function f(x) = 6x + 5.at n=25A023317
• Least prime in A031938 (lesser of primes differing by 20) whose distance to the next 20-twin is 6*n.at n=30A052359
• a(n) is smallest safe prime (A005385) such that a(n) + 12*n is the next safe prime, i.e., x = (a(n) - 1)/2 and x + 6*n are closest Sophie Germain primes.at n=15A059327
• a(n) is the prime the precedes the first occurrence of a prime gap of 2n where the product of the smallest prime factor of each composite number in the gap is minimal.at n=9A096318
• Primes p such that 5*p - 6 is square.at n=20A110482
• Number of base 11 circular n-digit numbers with adjacent digits differing by 1 or less.at n=9A124704
• Number of unordered rooted trees where each subtree from given node has the same number of nodes.at n=30A127524
• Primes of the form XYX, where Y is a single digit.at n=36A154270
• Primes of a Generalized Cunningham chain of length 9 by the function f(p) = 2 * p + 13.at n=3A176268
• Primes p such that q*p +- (p mod q) are primes, for q=8.at n=33A178416
• Number of distinct sums of reciprocals of parts of partitions of n.at n=43A212187
• Primes of the form abcabc..abcab.at n=21A228627
• Primes equal to a centered pentagonal number plus 1.at n=20A285810
• Yarborough primes that remain Yarborough primes when each of their digits are replaced by their squares.at n=41A296187
• Primes of the form k + A037276(k) in more than one way.at n=6A340636
• Primes p such that p^5 - 1 has 8 divisors.at n=28A341665
• Primes p such that p-1 is a partial sum of A014574.at n=17A343711
• Discriminants of imaginary quadratic fields with class number 39 (negated).at n=33A351677
• a(0) = 1; thereafter a(n) = 10*n^2 - 5*n + 2.at n=53A383466
• Primes having only {2, 7, 8} as digits.at n=22A385789