%I A084600
%S A084600 1,1,1,2,1,2,5,4,4,1,3,9,13,18,12,8,1,4,14,28,49,56,56,32,16,1,5,20,50,
%T A084600 105,161,210,200,160,80,32,1,6,27,80,195,366,581,732,780,640,432,192,64,
%U A084600 1,7,35,119,329,721,1337,2045,2674,2884,2632,1904,1120,448,128,1,8,44
%N A084600 Triangle, read by rows, where the n-th row lists the (2n+1) coefficients 
               of (1+x+2x^2)^n for n>=0.
%C A084600 Triangl by rows, X^n * [1,0,0,0,...]; where X = an infinite tridiagonal 
               matrix with (1,1,1,...) in the main and subdiagonals and (2,2,2,...) 
               in the subsubdiagonal. Also, X = an infinite triangular matrix with 
               (1,1,2,0,0,0,...) in each column. - Gary W. Adamson (qntmpkt(AT)yahoo.com), 
               May 26 2008
%C A084600 Row sums = (1, 4, 16, 64, 256,...). - Gary W. Adamson (qntmpkt(AT)yahoo.com), 
               May 26 2008
%e A084600 Rows:
%e A084600 {1},
%e A084600 {1,1,2},
%e A084600 {1,2,5,4,4},
%e A084600 {1,3,9,13,18,12,8},
%e A084600 {1,4,14,28,49,56,56,32,16},
%e A084600 {1,5,20,50,105,161,210,200,160,80,32},
%e A084600 {1,6,27,80,195,366,581,732,780,640,432,192,64},
%Y A084600 Cf. A002426, A084601-A084615.
%Y A084600 Sequence in context: A136457 A078016 A078046 this_sequence A167482 A137327 
               A143913
%Y A084600 Adjacent sequences: A084597 A084598 A084599 this_sequence A084601 A084602 
               A084603
%K A084600 nonn,tabl
%O A084600 0,4
%A A084600 Paul D. Hanna (pauldhanna(AT)juno.com), Jun 01 2003