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Number of 7'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 04:27:34

%S 0,0,0,0,0,0,1,1,1,1,1,1,1,1,2,3,4,5,6,7,8,9,11,12,14,15,17,18,20,21,

%T 24,25,27,29,31,32,35,36,39,41,43,44,48,49,51,53,57,58,61,62,65,68,70,

%U 71,76,78,82,85,89,91,96,99,105,108,111,113,120

%N Number of 7'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}], 7] - (n - 7); f[1] = f[2] = f[3] = f[4] = f[5] = f[6] = 0; Array[f, 67] (* _Robert G. Wilson v_, Nov 14 2012 *)

%Y Cf. A033094, A033096, A033098, A033100, A033102, A033104, A033106, A033107, A033110, A033112.

%K nonn,base

%O 1,15

%A _Clark Kimberling_