a(n) = n-th element of n-th row of triangle shown below.

Terms

a(0) =1a(1) =2a(2) =2a(3) =7a(4) =3a(5) =21a(6) =25a(7) =113a(8) =17a(9) =289a(10) =321a(11) =1665a(12) =769a(13) =5633a(14) =7169a(15) =30721a(16) =2049a(17) =69633a(18) =73729a(19) =409601a(20) =163841a(21) =1376257a(22) =1703937a(23) =7602177a(24) =1572865a(25) =19922945a(26) =23068673a(27) =113246209a(28) =58720257a(29) =385875969