Solutions a(n) to (r(n)-5)*(r(n)-6) = 21 *a(n)*(a(n)-1).

Terms

a(0) =1a(1) =2a(2) =5a(3) =22a(4) =34a(5) =161a(6) =494a(7) =2365a(8) =3685a(9) =17654a(10) =54281a(11) =260074a(12) =405262a(13) =1941725a(14) =5970362a(15) =28605721a(16) =44575081a(17) =213572042a(18) =656685485a(19) =3146369182a(20) =4902853594a(21) =23490982841a(22) =72229432934a(23) =346072004245a(24) =539269320205