37131domain: NAppears in sequencesNumbers k such that k and k^2 use only the digits 1, 3, 6, 7 and 8.at n=11A137038n*a(n+1) = (2*n^2+2n-1)*a(n) + (n+1)*a(n-1); a(0)=0, a(1)=1.at n=6A2599061/(Integral_{x=0..1} x^(x^(x^n)) dx - 1/2), rounded to the nearest integer.at n=40A322009