G.f. is the fourth power of the g.f. of A006950.

Terms

a(0) =1a(1) =4a(2) =10a(3) =24a(4) =55a(5) =116a(6) =230a(7) =440a(8) =819a(9) =1480a(10) =2602a(11) =4480a(12) =7580a(13) =12604a(14) =20620a(15) =33272a(16) =53029a(17) =83520a(18) =130088a(19) =200600a(20) =306488a(21) =464168a(22) =697150a(23) =1039032a(24) =1537435a(25) =2259300a(26) =3298428a(27) =4785880a(28) =6903657a(29) =9903040