Number of 3D matrices with positive integer entries such that sum of all entries equals n.

Terms

a(0) =1a(1) =4a(2) =10a(3) =25a(4) =58a(5) =130a(6) =286a(7) =620a(8) =1329a(9) =2827a(10) =5977a(11) =12559a(12) =26227a(13) =54493a(14) =112849a(15) =233272a(16) =481616a(17) =992955a(18) =2043238a(19) =4194649a(20) =8591014a(21) =17559133a(22) =35833948a(23) =73054885a(24) =148849186a(25) =303171755a(26) =617306563a(27) =1256452642a(28) =2555937826