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A033102
Number of 4's when k is written in base b for all b and k satisfying 2<=b<=n+1, 1<=k<=n.
10
0, 0, 0, 1, 1, 1, 1, 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 14, 16, 19, 21, 25, 27, 32, 35, 38, 40, 46, 50, 53, 56, 61, 64, 71, 73, 78, 82, 86, 91, 98, 101, 105, 109, 117, 121, 129, 133, 140, 148, 152, 155, 164, 169, 176, 180, 186, 190, 198, 204
OFFSET
1,9
MATHEMATICA
f[n_] := Count[ Flatten@ Table[ IntegerDigits[k, b], {k, n}, {b, 2, n + 1}], 4] - (n - 4); f[1] = f[2] = f[3] = 0; Array[f, 59] (* Robert G. Wilson v, Nov 14 2012 *)
KEYWORD
nonn,base
STATUS
approved