21817

Properties

Appears in sequences

• Primes from merging of 5 successive digits in decimal expansion of e.at n=11A104846
• Numbers k such that k, k+1, k+2 and k+3 are 1,2,3,4-almost primes.at n=21A113000
• Prime numbers p such that p +- ((p-1)/4) are primes.at n=22A137705
• Prime numbers p such that p +- ((p-1)/6) are primes.at n=23A137724
• Least prime P such that 3*p(n)*P*(3*p(n)*P+1)-1, 3*p(n)*P*(3*p(n)*P+1)+1,3*p(n)*P*(3*p(n)*P+3)-1,3*p(n)*P*(3*p(n)*P+3)+1 are all primes with p(i) = i-th prime.at n=26A137839
• a(n) = (2^(2+n)-(-1)^n)/3 - 2*n.at n=14A141025
• Primes congruent to 46 mod 59.at n=39A142773
• Primes of the form x^2 + 29*(x+1)^2.at n=5A176695
• Primes that are the average of the members of emirp pairs.at n=12A178581
• Nonpalindromic primes that are the average of the members of emirp pairs.at n=4A178585
• Least prime p such that 3 + 4*prime(p*n) = 5*prime(q*n) for some prime q.at n=40A260886
• Let F(g,p) be the frequency of g up to prime nextprime(p+1). Primes p such that F(2,p) = F(4,p) and g = 2 or 4.at n=42A274122
• Table in which the g.f. of row n, R(n,x), satisfies Sum_{k=-oo..+oo} (-1)^k * (x^k + n*R(n,x))^k = 1 + (n+2)*Sum_{k>=1} (-1)^k * x^(k^2), for n >= 1, as read by antidiagonals.at n=77A370020
• Expansion of g.f. A(x) satisfying Sum_{n=-oo..+oo} (-1)^n * (x^n + A(x))^n = 1 + 3*Sum_{n>=1} (-1)^n * x^(n^2).at n=11A370021
• Prime numbersat n=2447