508031496000domain: NAppears in sequencesBishops on an n X n board (see Robinson paper for details).at n=16A005634a(0) = 21; for n > 0, a(n) is the smallest triangular number which is a (proper) multiple of a(n-1).at n=6A068142a(0) = 15; for n > 0, a(n) is the smallest triangular number which is a (proper) multiple of a(n-1).at n=5A068513