Number of compositions of odd natural numbers into 4 parts <= n.

Terms

a(0) =0a(1) =8a(2) =40a(3) =128a(4) =312a(5) =648a(6) =1200a(7) =2048a(8) =3280a(9) =5000a(10) =7320a(11) =10368a(12) =14280a(13) =19208a(14) =25312a(15) =32768a(16) =41760a(17) =52488a(18) =65160a(19) =80000a(20) =97240a(21) =117128a(22) =139920a(23) =165888a(24) =195312a(25) =228488a(26) =265720a(27) =307328a(28) =353640a(29) =405000