21569

Properties

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 82 ones.at n=27A031850
• Sum of the lengths of the cycle types of the permutation created by duality and reversal on the partitions of n.at n=36A036050
• Fourth term of weak prime sextet: p(m-2)-p(m-3) < p(m-1)-p(m-2) < p(m)-p(m-1) < p(m+1)-p(m) < p(m+2)-p(m+1).at n=7A054831
• Primes which can be expressed as sum of distinct powers of 4.at n=30A077718
• Value of C in y = x^2+7x+C such that y is prime for all x = 0 to 4.at n=28A097436
• Numerators of partial sums of (p+q)/p*q, where p and q are primes.at n=5A120833
• Primes p such that p*q-p-q and p*q+p+q are prime where q=nextprime(p).at n=39A128548
• Primes of the form 41+(n+n^2)/2=41+A000217(n).at n=26A139219
• Primes congruent to 36 mod 61.at n=39A142834
• Primes p such that 12*p^3+-1 are twin primes.at n=15A158297
• Integers n such that the century defined by the interval [100n+1, 100n+100] (i.e., the (n+1)-st century) contains exactly one Ormiston prime pair and no other primes.at n=2A162895
• Numbers k such that Sum_{i=1..k} i^6 divides Product_{i=1..k} i^6.at n=17A166606
• Pythagorean primes p such that for all primes q < p, p XOR q is not equal to p - q.at n=27A197918
• a(n) is the number of digits in the decimal representation of the smallest power of n that contains nine consecutive identical digits.at n=4A217184
• a(n) is the number of digits in the decimal representation of the smallest power of n that contains nine consecutive identical digits.at n=34A217184
• a(n) is the number of digits in the decimal representation of the smallest power of 6 that contains n consecutive identical digits.at n=8A217188
• a(n) is the number of digits in the decimal representation of the smallest power of 6 that contains n consecutive identical digits.at n=9A217188
• Primes whose base-4 representation also is the base 2-representation of a prime.at n=19A235461
• Primes equal to a centered heptagonal number plus 1.at n=16A285811
• Greatest of 4 consecutive primes with consecutive gaps 2, 4, 6.at n=26A290706