%I #9 Jun 18 2013 12:16:14
%S 1,2,2,3,3,4,4,4,5,6,5,5,6,7,8,6,6,7,8,9,10,7,7,8,9,10,11,12,8,8,9,10,
%T 11,12,13,14,9,9,10,11,12,13,14,15,16,10,10,11,12,13,14,15,16,17,18,
%U 11,11,12,13,14,15,16,17,18,19,20,12,12,13,14,15,16
%N Triangle read by rows: row n consists of n followed by the numbers n through 2n-2.
%C Row sums = A005448.
%F T(n,1)=n, T(n,k)=n+k-2 for 2<=k<=n. G.f.=z(1-2tz+2zt^2-t^3*z^3)/[(1-z)(1-tz)]^2. - _Emeric Deutsch_, Nov 24 2007
%e First few rows of the triangle are:
%e 1;
%e 2, 2;
%e 3, 3, 4;
%e 4, 4, 5, 6;
%e 5, 5, 6, 7, 8;
%e 6, 6, 7, 8, 9, 10;
%e 7, 7, 8, 9, 10, 11, 12;
%e ...
%p T:=proc(n,k) if n<k then 0 elif k=1 then n else n+k-2 end if end proc: for n to 10 do seq(T(n,k),k=1..n) end do; # yields sequence in triangular form - _Emeric Deutsch_, Nov 24 2007
%t Flatten[Table[Join[{n},Range[n,2n-2]],{n,12}]] (* _Harvey P. Dale_, Jun 18 2013 *)
%Y Cf. A005448.
%K nonn,tabl
%O 1,2
%A _Gary W. Adamson_, Oct 27 2007
%E Corrected and extended by _Harvey P. Dale_, Jun 18 2013