|
%I #7 Jul 20 2021 11:36:38
%S 1,2,3,4,7,18,49,120,265,554,1155,2476,5455,12138,26881,58992,128689,
%T 280466,612579,1341268,2940151,6443778,14111857,30886632,67590649,
%U 147934010,323850531,709047292,1552412671,3398703066,7440375937
%N Expansion of (1-x)^2/((1-x)^4-2x^4).
%C Row sums of A119329. Binomial transform of A119332, or (1,1,0,0,2,2,0,0,4,4,...).
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,1).
%F a(n)=4a(n-1)-6a(n-2)+4a(n-3)+a(n-4); a(n)=sum{k=0..n, sum{j=0..n-k, C(k,2j)C(n-k,2j)*2^j}}.
%t CoefficientList[Series[(1-x)^2/((1-x)^4-2x^4),{x,0,50}],x] (* or *) LinearRecurrence[{4,-6,4,1},{1,2,3,4},50] (* _Harvey P. Dale_, Jul 20 2021 *)
%K easy,nonn
%O 0,2
%A _Paul Barry_, May 14 2006
|
