G.f.: (1+44*x+339*x^2+630*x^3+323*x^4+42*x^5+x^6)/(1-x)^7.

Terms

a(0) =1a(1) =51a(2) =675a(3) =4319a(4) =18131a(5) =58121a(6) =154701a(7) =359605a(8) =754189a(9) =1459111a(10) =2645391a(11) =4546851a(12) =7473935a(13) =11828909a(14) =18122441a(15) =26991561a(16) =39219001a(17) =55753915a(18) =77733979a(19) =106508871a(20) =143665131a(21) =191052401a(22) =250811045a(23) =325401149a(24) =417632901a(25) =530698351