18917

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 73.at n=13A020412
• Odd numbers in sorted order from generation 2 onwards.at n=32A048462
• Smallest prime occurring in generation n (0 if none).at n=11A048463
• Distinct primes in sorted order from generation 2 onwards.at n=15A048465
• Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 21.at n=22A051962
• Primes of the form k(k+1)/2+2 (i.e., two more than a triangular number).at n=38A055472
• Primes p such that p and p+2 are twin primes and also the strings 987654321p and 987654321p+2 are twin primes.at n=8A103818
• Denominators associated with A109139.at n=9A109140
• Prime quadruples: 3rd term.at n=17A136721
• Primes congruent to 37 mod 59.at n=39A142764
• Minimum numbers whose phi of phi are multiples of the n-th prime: the n-th term is the minimum integer x such that: prime(n) | phi(phi(x)), prime(n) being the n-th prime.at n=44A167766
• Number of 2 X 2 matrices having all terms in {1,...,n} and positive determinant.at n=13A211059
• Primes of the form 15*k^2 - 15*k + 17.at n=25A220081
• a(n) is the total number of rows of circles of radius r packing into a circle of radius R, where r = R/2^n.at n=14A239206
• Primes having primitive roots 2, 3, 5, 7, and 11.at n=37A241046
• Primes having primitive roots 2, 3, 5, 7, 11, and 13.at n=17A241047
• Primes of the form 2*n^2+86*n+41.at n=26A243958
• Primes of the form 2k^2 + k + 2.at n=17A249606
• Number of (n+1) X (7+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries.at n=8A251148
• Twin primes both of which are the sum of three positive cubes.at n=12A272376