A084606 - OEIS

%I #7 Aug 01 2013 09:30:12

%S 1,1,2,2,1,4,8,8,4,1,6,18,32,36,24,8,1,8,32,80,136,160,128,64,16,1,10,

%T 50,160,360,592,720,640,400,160,32,1,12,72,280,780,1632,2624,3264,

%U 3120,2240,1152,384,64,1,14,98,448,1484,3752,7448,11776,14896,15008,11872

%N Triangle, read by rows, where the n-th row lists the (2n+1) coefficients of (1+2x+2x^2)^n.

%e Rows:

%e {1},

%e {1,2,2},

%e {1,4,8,8,4},

%e {1,6,18,32,36,24,8},

%e {1,8,32,80,136,160,128,64,16},

%e {1,10,50,160,360,592,720,640,400,160,32},

%e {1,12,72,280,780,1632,2624,3264,3120,2240,1152,384,64},

%o (PARI) for(n=0,15, for(k=0,2*n,t=polcoeff((1+2*x+2*x^2)^n,k,x); print1(t",")); print(" "))

%Y Cf. A002426, A084600-A084605, A006139, A084608-A084615.

%K nonn,tabf

%O 0,3

%A _Paul D. Hanna_, Jun 01 2003