28081

Properties

Appears in sequences

• Primes that remain prime through 4 iterations of the function f(x) = 9x + 8.at n=12A023326
• Numbers whose least quadratic nonresidue (A020649) is 17.at n=22A025026
• Numbers having four 6's in base 8.at n=25A043448
• Primes with 19 as smallest positive primitive root.at n=25A061331
• a(n) = min{ m : sum_{n <= i <= m} 1/p_i > 1}, where p_i is the i-th prime = A000040(i).at n=25A092325
• Primes p such that there exist three primes q, r and s with p^3=q^3+r^3+s^3.at n=30A114923
• Primes of the form p=floor(T/6), T are triangular numbers.at n=31A171595
• Primes of the form 2*n^2+6*n+1.at n=19A176549
• Centered 36-gonal numbers.at n=39A195316
• Primes of the form 10n^2 - 9.at n=19A201964
• Number of n X 3 0..1 arrays avoiding 0 0 0 horizontally and 0 1 1 vertically.at n=6A206931
• T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 horizontally and 0 1 1 vertically.at n=42A206936
• Number of 7Xn 0..1 arrays avoiding 0 0 0 horizontally and 0 1 1 vertically.at n=2A206940
• a(n) is the smallest prime such that it and the previous two primes are all of the form x^2 + n * y^2.at n=35A212603
• a(n) = 1+2*(d1 + 1)*(d2 + 1)*...*(dk + 1), where d1, d2, ..., dk are the prime factors of the n-th Fermat pseudoprime to base 2 A001567(n).at n=27A216646
• Primes p such that p = 361 + 420*k for some k.at n=27A217656
• Lesser of consecutive primes whose sum is of the form k*(k+2), for some integer k.at n=26A242384
• Primes corresponding to terms of A248145.at n=11A248146
• Primes p such that the maximal length of a nontrivial N(p)-Hensley sequence mod p is less than the value of A124882 for that prime, where N(p) is the least positive quadratic non-residue mod p.at n=14A261405
• P(n,k) is an array read by rows, with n > 0 and k=1..5, where row n gives the chain of 5 consecutive primes {p(i), p(i+1), p(i+2), p(i+3), p(i+4)} having the symmetrical property p(i) + p(i+4) = p(i+1) + p(i+3) = 2*p(i+2) for some index i.at n=13A267028