Number of length n 1..(2+1) arrays with every leading partial sum divisible by 2, 3, 5 or 7.

Terms

a(0) =2a(1) =6a(2) =18a(3) =50a(4) =105a(5) =181a(6) =316a(7) =560a(8) =969a(9) =1777a(10) =3699a(11) =8370a(12) =18297a(13) =36978a(14) =73912a(15) =155816a(16) =335928a(17) =697052a(18) =1360137a(19) =2539247a(20) =4757378a(21) =9452951a(22) =20357207a(23) =46362252a(24) =107298090a(25) =244529803a(26) =538892048a(27) =1146917302a(28) =2392827002a(29) =4981802096