Triangle of coefficients in expansion of (1+9x)^n.

Terms

a(0) =1a(1) =1a(2) =9a(3) =1a(4) =18a(5) =81a(6) =1a(7) =27a(8) =243a(9) =729a(10) =1a(11) =36a(12) =486a(13) =2916a(14) =6561a(15) =1a(16) =45a(17) =810a(18) =7290a(19) =32805a(20) =59049a(21) =1a(22) =54a(23) =1215a(24) =14580a(25) =98415a(26) =354294a(27) =531441a(28) =1a(29) =63