G.f.: 1/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5))^2.

Terms

a(0) =1a(1) =2a(2) =5a(3) =10a(4) =20a(5) =36a(6) =63a(7) =104a(8) =169a(9) =264a(10) =405a(11) =604a(12) =888a(13) =1278a(14) =1815a(15) =2536a(16) =3502a(17) =4772a(18) =6437a(19) =8586a(20) =11352a(21) =14866a(22) =19315a(23) =24890a(24) =31851a(25) =40466a(26) =51089a(27) =64092a(28) =79952a(29) =99172