a(n) = Sum_{i=1..n} binomial(i+1,2)^5.

Terms

a(0) =1a(1) =244a(2) =8020a(3) =108020a(4) =867395a(5) =4951496a(6) =22161864a(7) =82628040a(8) =267156165a(9) =770440540a(10) =2022773116a(11) =4909947484a(12) =11150268935a(13) =23913084560a(14) =48796284560a(15) =95322158736a(16) =179163294729a(17) =325374464580a(18) =572984364580a(19) =981394464580