118481007099domain: NAppears in sequencesIndices of triangular numbers that are ten times other triangular numbers.at n=21A341895Integers x such that there exists y, x>y>=1, satisfying (y+1)/(x+1) = (x||(y+1))/(y||(x+1)) where z||t is the concatenation of z and t.at n=10A342387