278832

Appears in sequences

• a(n) is the least positive integer k such that g(k) = n*g(k-1), where g(k) = prime(k+1) - prime(k).at n=21A078563
• Largest k such that round(1/(sqrt(prime(k+1))-sqrt(prime(k)))) = n where prime(n) denotes the n-th prime (conjectured values).at n=29A078693
• First occurrence of just n semiprimes occurs between the a(n)-th prime and the next prime.at n=35A103669
• Numbers k such that k and k^2 use only the digits 2, 3, 4, 7 and 8.at n=17A137074
• a(n) = 484*n^2 + 2*n.at n=23A158325
• 1/7 the number of n X 2 0..6 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=5A185405
• T(n,k)=1/7 the number of nXk 0..6 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=22A185409
• T(n,k)=1/7 the number of nXk 0..6 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=26A185409