77875domain: NAppears in sequencesNumbers k such that the period of the continued fraction for sqrt(k) contains exactly 43 ones.at n=13A031811a(n) = 5*A097780(n-2).at n=4A154022Odd numbers k > 1 such that A309906(k-1) < A309906(k) > A309906(k+1) < A309906(k+2) > A309906(k+3).at n=18A349938