19793

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 91.at n=11A020430
• Binomial transform of {b(n)}, where b(n)=1 for prime n and b(n)=0 otherwise.at n=16A052467
• a(n) = ceiling(binomial(n,6)/n).at n=29A053643
• Primes p such that x^48 = 2 has no solution mod p, but x^24 = 2 has a solution mod p.at n=27A059669
• Let u(1) = x and u(n+1) = (n^2/u(n)) + 1 for n >= 1; then a(n) is such that u(n) = (b(n)*x + c(n))/(d(n)*x + a(n)) (in lowest terms) and a(n), b(n), c(n), d(n) are positive integers.at n=15A075829
• Primes p such that p's set of distinct digits is {1,3,7,9}.at n=15A108386
• a(n) is the difference between denominator and numerator of the n-th alternating harmonic number Sum_{k=1..n} (-1)^(k+1)/k = A058313(n)/A058312(n).at n=14A119248
• Primes of the form p^2 + q^10 where p and q are primes.at n=10A122716
• Primes congruent to 24 mod 53.at n=38A142554
• Primes congruent to 28 mod 59.at n=35A142755
• Emirps using each of the digits 1, 3, 7, 9 at least once, but no others.at n=6A158917
• Primes of the form 5*x^2 - 3*y^2, where x and y are consecutive numbers.at n=26A176470
• Number of idempotents in Identity Difference Partial Transformation semigroup.at n=8A190531
• Primes p such that A179382((p+1)/2) = (p-1)/16.at n=34A225759
• Prime p1 of consecutive primes p1, p2, where p2 - p1 = 8, and p1, p2 are in different centuries.at n=14A287049
• Largest nonrepunit base-n absolute prime (conjectured).at n=9A317689
• Primes p such that 2*p+q and 2*p+r are prime, where q and r are the next two primes after p.at n=37A340225
• Primes in A340180.at n=34A342644
• Primes that are the first in a run of exactly 3 emirps.at n=39A346023
• Prime numbersat n=2240