44349domain: NAppears in sequencesa(1) = a(2) = 1; a(n) = ( Sum_{i|(n-1)} a(i) ) + Sum_{j|(n-2)} a(j).at n=20A293636Where records of A309036 occur.at n=12A309056Number of intersection points when every pair of vertices of a row of n adjacent congruent rectangles are joined by an infinite line.at n=20A347750