One half of sixth column (m=5) of triangle A060556.

Terms

a(0) =3a(1) =43a(2) =311a(3) =1551a(4) =6061a(5) =19877a(6) =57057a(7) =147433a(8) =349778a(9) =773058a(10) =1609322a(11) =3182842a(12) =6021366a(13) =10956806a(14) =19264366a(15) =32851038a(16) =54506573a(17) =88232485a(18) =139667385a(19) =216629985a(20) =329804475a(21) =493596675a(22) =727193415a(23) =1055862015