a(n)=the sum of the (1,2)- and (1,3)-entries and twice the (1,4)-entry of the matrix P^n + T^n, where the 4 X 4 matrices P and T are defined by P=[0,1,0,0;0,0,1,0;0,0,0,1;1,0,0,0] and T=[0,1,0,0;0,0,1,0;0,0,0,1;1,1,1,1].

A109525

a(n)=the sum of the (1,2)- and (1,3)-entries and twice the (1,4)-entry of the matrix P^n + T^n, where the 4 X 4 matrices P and T are defined by P=[0,1,0,0;0,0,1,0;0,0,0,1;1,0,0,0] and T=[0,1,0,0;0,0,1,0;0,0,0,1;1,1,1,1].

Terms

    a(0) =0a(1) =2a(2) =2a(3) =4a(4) =4a(5) =9a(6) =16a(7) =31a(8) =56a(9) =109a(10) =209a(11) =403a(12) =773a(13) =1491a(14) =2873a(15) =5538a(16) =10671a(17) =20570a(18) =39649a(19) =76426a(20) =147312a(21) =283954a(22) =547338a(23) =1055028a(24) =2033628a(25) =3919945a(26) =7555936a(27) =14564535a(28) =28074040a(29) =54114453

External references