47730

Appears in sequences

• Numbers k such that 2k+1, 4k+1, 6k+1 and 8k+1 are primes.at n=25A124409
• Primitive (squarefree) elements of A199745.at n=37A200145
• Consider a non-palindromic number of k digits n = d_(k)*10^(k-1) + d_(k-1)*10^(k-2) + … + d_(2)*10 + d_(1). Sequence lists the numbers n such that Sum_{i=1..k-1}{phi(Sum_{j=1..i}{d_(j)*10^(j-1)})} = Sum_{i=1..k-1}{phi(Sum_{j=1..i}{d_(k-j+1)*10^(i-j)})} (see example below).at n=43A241503
• Antidiagonal sums of the array defined in A385623.at n=39A385624