Sheffer triangle (exp(x), exp(3*x) - 1). Named S2[3,1].

Terms

a(0) =1a(1) =1a(2) =3a(3) =1a(4) =15a(5) =9a(6) =1a(7) =63a(8) =108a(9) =27a(10) =1a(11) =255a(12) =945a(13) =594a(14) =81a(15) =1a(16) =1023a(17) =7380a(18) =8775a(19) =2835a(20) =243a(21) =1a(22) =4095a(23) =54729a(24) =109890a(25) =63180a(26) =12393a(27) =729a(28) =1a(29) =16383