28069

Properties

Appears in sequences

• Number of n-step spirals on hexagonal lattice.at n=21A006777
• Numbers k such that the continued fraction for sqrt(k) has period 65.at n=29A020404
• Numerators of b(n) = (1/16^n)*(4/(8*n+1) - 2/(8*n+4) - 1/(8*n+5) - 1/(8*n+6)).at n=21A048581
• Doubly balanced primes: primes which are averages of both their immediate and their second neighbors.at n=2A051795
• Primes p such that p-12, p and p+12 are consecutive primes.at n=27A053072
• Duplicate of A051795.at n=2A081416
• Primes p such that the sum of the digits of p is not prime, but the sum of each digit raised to the 4th power is prime.at n=26A091368
• Numbers p such that p = (prime(n)+ prime(n+2))/2 is prime for prime indices n=2, 3, 5...at n=28A098038
• Primes arising in A073946.at n=15A113943
• Numbers of ways in which a unit disc can be dissected into 6n curvilinear triangles, at least one of which does not contain the center.at n=32A193362
• 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=12A267028
• Primes p such that 2*p + 31 is a square.at n=14A269786
• Numbers k such that (73*10^k + 413)/9 is prime.at n=20A290431
• Balanced primes of order one ending in 9.at n=6A303095
• Prime numbersat n=3062