Number of plane partitions (or planar partitions) of n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =13a(5) =24a(6) =48a(7) =86a(8) =160a(9) =282a(10) =500a(11) =859a(12) =1479a(13) =2485a(14) =4167a(15) =6879a(16) =11297a(17) =18334a(18) =29601a(19) =47330a(20) =75278a(21) =118794a(22) =186475a(23) =290783a(24) =451194a(25) =696033a(26) =1068745a(27) =1632658a(28) =2483234a(29) =3759612