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Number of 3's when k is written in base b for all b and k satisfying 2<=b<=n+1, 1<=k<=n.
10

%I #7 Nov 15 2012 04:26:31

%S 0,0,1,1,1,1,2,3,4,5,7,9,12,14,19,21,24,28,33,35,40,43,49,53,57,60,68,

%T 73,78,84,92,95,103,107,114,119,124,130,140,145,151,158,169,175,185,

%U 191,200,209,216,222,235,242,251,260,271,278

%N Number of 3's when k is written in base b for all b and k satisfying 2<=b<=n+1, 1<=k<=n.

%t f[n_] := Count[ Flatten@ Table[ IntegerDigits[k, b], {k, n}, {b, 2, n + 1}], 3] - (n - 3); f[1] = f[2] = 0; Array[f, 56] (* _Robert G. Wilson v_, Nov 14 2012 *)

%Y Cf. A033094, A033096, A033098, A033099, A033102, A033104, A033106, A033108, A033110, A033112.

%K nonn,base

%O 1,7

%A _Clark Kimberling_