Number of 4's when k is written in base b for all b and k satisfying 2<=b<=n+1, 1<=k<=n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =1a(5) =1a(6) =1a(7) =1a(8) =2a(9) =3a(10) =4a(11) =5a(12) =6a(13) =8a(14) =9a(15) =11a(16) =12a(17) =14a(18) =16a(19) =19a(20) =21a(21) =25a(22) =27a(23) =32a(24) =35a(25) =38a(26) =40a(27) =46a(28) =50a(29) =53