The (1,2)-entry in the 3 X 3 matrix M^n, where M = {{2, 1, 1}, {1, 1, 0}, {1, 0, 0}}.

Terms

a(0) =0a(1) =1a(2) =3a(3) =9a(4) =26a(5) =75a(6) =216a(7) =622a(8) =1791a(9) =5157a(10) =14849a(11) =42756a(12) =123111a(13) =354484a(14) =1020696a(15) =2938977a(16) =8462447a(17) =24366645a(18) =70160958a(19) =202020427a(20) =581694636a(21) =1674922950a(22) =4822748423a(23) =13886550633a(24) =39984728949a(25) =115131438424a(26) =331507764639a(27) =954538564968