19867

Properties

Appears in sequences

• Least m such that if r and s in {1/1, 1/3, 1/6,..., 1/C(n+1,2)} satisfy r < s, then r < k/m < s for some integer k.at n=46A024826
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 80 ones.at n=18A031848
• The smallest initial prime of 2 non-overlapping d-twin primes if the distance between pairs (D) is minimal (see A052380).at n=10A052381
• Primes p such that q-p = 22, where q is the next prime after p.at n=36A061779
• Centered 22-gonal numbers.at n=42A069173
• Primes with digit sum = 31.at n=32A106767
• a(n) = (5*n^3+12*n^2+n+6)/6.at n=28A114211
• Primes p such that q = 4p^2 + 1 and r = 4q^2 + 1 are also prime.at n=27A122424
• Primes congruent to 42 mod 61.at n=35A142840
• Transform of the finite sequence (1, 0, -1, 0, 1, 0, -1) by the T_{1,1} transform (see link).at n=11A159331
• Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,3,9, Q starts with 2,6, R starts with 4; at each stage the smallest number not yet present in P,Q,R is appended to R. Sequence gives P.at n=43A225385
• Smallest of the first four consecutive primes that comprise two sets of primes with difference 2*n.at n=10A226657
• Primes p such that p-1 is squarefree and all prime divisors of p-1 other than 11 are also in the sequence.at n=28A267504
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 489", based on the 5-celled von Neumann neighborhood.at n=29A272512
• Centered 21-gonal primes.at n=8A276261
• Centered 22-gonal primes.at n=20A276262
• a(n) = numerator of Sum_{1 <= i < j <= d(n)} 1/(d_j - d_i), sum over ordered pairs of divisors of n, where d(n) is the number of divisors of n.at n=19A330077
• a(n) is the first prime p such that q*r mod p = q*r mod s = 12*n, where q,r,s are the next three primes after p.at n=43A338615
• Prime numbersat n=2248