a(n) = Sum_{i=1..n} binomial(i+1,2)^3.

Terms

a(0) =1a(1) =28a(2) =244a(3) =1244a(4) =4619a(5) =13880a(6) =35832a(7) =82488a(8) =173613a(9) =339988a(10) =627484a(11) =1102036a(12) =1855607a(13) =3013232a(14) =4741232a(15) =7256688a(16) =10838265a(17) =15838476a(18) =22697476a(19) =31958476a(20) =44284867a(21) =60479144a(22) =81503720a(23) =108503720a(24) =142831845a(25) =186075396a(26) =240085548a(27) =307008964a(28) =389321839