Triangular array formed by the Mersenne numbers.

Terms

a(0) =1a(1) =3a(2) =1a(3) =7a(4) =6a(5) =1a(6) =15a(7) =23a(8) =9a(9) =1a(10) =31a(11) =72a(12) =48a(13) =12a(14) =1a(15) =63a(16) =201a(17) =198a(18) =82a(19) =15a(20) =1a(21) =127a(22) =522a(23) =699a(24) =420a(25) =125a(26) =18a(27) =1a(28) =255a(29) =1291