Triangle read by rows: t(n,k)=t(n - 1, k - 1) + 4* t(n - 1, k) + 3*t(n - 1, k - 1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =8a(5) =1a(6) =1a(7) =36a(8) =36a(9) =1a(10) =1a(11) =148a(12) =288a(13) =148a(14) =1a(15) =1a(16) =596a(17) =1744a(18) =1744a(19) =596a(20) =1a(21) =1a(22) =2388a(23) =9360a(24) =13952a(25) =9360a(26) =2388a(27) =1a(28) =1a(29) =9556