18799

Appears in sequences

• Numbers n such that 265*2^n-1 is prime.at n=25A050891
• a(n) is the least x such that the n values x+0, x+6, x+12, ..., x+6*(n-1) are all products of exactly two primes (i.e., semiprimes).at n=9A091016
• Subprimorials: inverse binomial transform of primorials (A002110).at n=6A121572
• Balanced ternary Keith numbers.at n=10A188380
• The Wiener index of the double-comb graph \/_\/_\/...\/_\/ with 3n (n>=1) nodes. The Wiener index of a connected graph is the sum of the distances between all unordered pairs of vertices in the graph.at n=21A192025
• The number of primes of the form i^2 + j^4 (A028916) <= 2^n.at n=23A226498
• Odd integers k such that for every m >= 1 the numbers k*4^m - 1 have at least three prime factors, not necessarily distinct, and k*4^m - 1 has at least two-element covering set.at n=29A233552
• Number of partitions p of n such that (number of numbers of the form 5k + 4 in p) is a part of p.at n=40A241553
• Number k such that k^2 + 1 = p*q*r where p,q,r are distinct primes and the sum p+q+r is a perfect square.at n=11A261529
• Partial sums of A299274.at n=30A299275
• a(n) = 25*n^2/2 - 11*n/2 + 1.at n=39A383465