A339028 Triangle T(n,m) = 3*(m+1)*C(n+m+3,m)*C(2*n+2,n-m)/((n+m+3)*C(n+1,m)).
1, 3, 3, 9, 12, 9, 28, 42, 42, 28, 90, 144, 162, 144, 90, 297, 495, 594, 594, 495, 297, 1001, 1716, 2145, 2288, 2145, 1716, 1001, 3432, 6006, 7722, 8580, 8580, 7722, 6006, 3432, 11934, 21216, 27846, 31824, 33150, 31824, 27846, 21216, 11934, 41990, 75582, 100776, 117572, 125970, 125970, 117572, 100776, 75582, 41990
Offset: 0
Examples
1, 3,3, 9,12,9, 28,42,42,28, 90,144,162,144, 90,297,495,594,594,495,297
Programs
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Maxima
T(n,m):=if n
Formula
G.f. ((sqrt(1-4*x*y)-sqrt(1-4*x))/(2*(x-x*y)))^3.