a(n) = 1*(n) + 2*(n-1) + 3*(n-2) + ... + (n+1-k)*k, where k = floor((n+1)/2).

Terms

a(0) =1a(1) =2a(2) =7a(3) =10a(4) =22a(5) =28a(6) =50a(7) =60a(8) =95a(9) =110a(10) =161a(11) =182a(12) =252a(13) =280a(14) =372a(15) =408a(16) =525a(17) =570a(18) =715a(19) =770a(20) =946a(21) =1012a(22) =1222a(23) =1300a(24) =1547a(25) =1638a(26) =1925a(27) =2030a(28) =2360a(29) =2480