28051

Properties

Appears in sequences

• Primes prime(k) such that prime(k)*k falls between twin primes.at n=19A080174
• Primes of the form k^2 - 7*k + 7.at n=34A089376
• a(0)=1, a(1)=1, a(n) = 11*a(n/2) for even n, and a(n) = 10*a((n-1)/2) + a((n+1)/2) for odd n >= 3.at n=25A116525
• Primes of the form 2n^2+18n+7, n>=0.at n=15A154592
• Primes p such that (p+18), (p+36) and (p+72) are also prime.at n=31A175158
• Constant term of the reduction of n-th polynomial at A158983 by x^2->x+2.at n=3A192342
• Expansion of g.f. (1-2*x+51*x^2)/(1-x)^3.at n=34A257352
• Primes p such that prime(p)^2 - 2 = prime(q) for some prime q.at n=30A261354
• 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=10A267028
• Centered 22-gonal primes.at n=23A276262
• Primes p whose reverse q is a semiprime, and of p+q and its reverse one is a prime and the other is a semiprime.at n=39A350781
• Discriminants of imaginary quadratic fields with class number 31 (negated).at n=30A351669
• a(n) = Sum_{k=0..n} 5^k * 2^(n-k) * binomial(n+k-1,k).at n=4A386766
• Prime numbersat n=3060