a(n) = floor( Product_{k>=0} (1 + n/k!) ).

Terms

a(0) =1a(1) =7a(2) =26a(3) =69a(4) =151a(5) =293a(6) =519a(7) =862a(8) =1361a(9) =2062a(10) =3019a(11) =4297a(12) =5969a(13) =8121a(14) =10848a(15) =14261a(16) =18481a(17) =23646a(18) =29908a(19) =37437a(20) =46419a(21) =57061a(22) =69586a(23) =84242a(24) =101297a(25) =121042a(26) =143793a(27) =169893a(28) =199710a(29) =233642