25848

Appears in sequences

• Numbers k such that k!!!!!! - 1 is prime.at n=19A051592
• Numbers k such that k | sigma_9(k) - phi(k)^9.at n=31A055703
• Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 19 (most significant digit on right).at n=27A061972
• Numbers n such that 4*10^n + 3*R_n + 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=28A102989
• Number of base 12 n-digit numbers with adjacent digits differing by two or less.at n=6A126399
• G.f. satisfies: A(x) = (1+x) * A(x^2)*A(x^3)*A(x^4)*...*A(x^n)*...at n=36A129373
• Average of twin prime pairs with multiple and strictly distinct powers.at n=30A177426
• Averages k of twin primes such that the sum (with multiplicity) of prime factors of k-1, k and k+1 is prime.at n=46A340060
• Midpoints k of a pair of twin primes such that sigma(k) is also the midpoint of a pair of twin primes.at n=36A349981