21067

Properties

Appears in sequences

• Primes that remain prime through 4 iterations of function f(x) = 9x + 10.at n=14A023327
• Primes that remain prime through 5 iterations of function f(x) = 9x + 10.at n=4A023355
• Discriminants of imaginary quadratic fields with class number 17 (negated).at n=34A046014
• Euclid-Mullin sequence (A000945) with initial value a(1)=8191 instead of a(1)=2.at n=19A051334
• a(n) is the n-th prime whose decimal expansion begins with the decimal expansion of n.at n=20A077345
• Primes congruent to 22 mod 61.at n=38A142820
• Depression-type primes with five digits; from left to right digits decrease to and increase from the central digit.at n=5A157083
• Primes of the form n^2+42.at n=21A174812
• Primes of the form floor(k^sqrt(Pi)).at n=41A180452
• a(n) = gpf(1 + Product_{k=0..4} prime(n+k)), where gpf is greatest prime factor and prime(i) is the i-th prime.at n=14A261210
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 470", based on the 5-celled von Neumann neighborhood.at n=37A272421
• Number of nonagons that can be formed with perimeter n.at n=44A288255
• Number of partitions of n such that 4*(greatest part) >= (number of parts).at n=36A347868
• Primes in A239237.at n=14A361252
• Primes p such that p, q and p + q but not q - p have distinct digits, where q is the next prime after p.at n=0A371354
• a(n) = 4^n - 3^n - n*3^(n-1) - binomial(n,2)*3^(n-2).at n=8A384415
• Prime numbersat n=2370