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%I #17 Apr 22 2021 22:09:28
%S 0,1,2,3,4,5,6,8,9,10,11,12,13,14,15,16,1,18,19,20,21,22,23,24,25,26,
%T 2,28,29,30,31,32,33,34,35,36,3,38,39,40,41,42,43,44,45,46,4,48,49,50,
%U 51,52,53,54,55,56,5,58,59,60,61,62,63,64,65,66,6,68,69,0,1,2
%N Delete all 7's from the sequence of nonnegative integers.
%o (Python)
%o def A004726(n):
%o l = len(str(n))
%o m = 7*(10**l-1)//9
%o k = n + l - int(n+l < m)
%o return 6 if k == m else int(str(k).replace('7','')) # _Chai Wah Wu_, Apr 20 2021
%Y Cf. A004719, A004720, A004721, A004722, A004723, A004724, A004725, A004727, A004728.
%K base,nonn
%O 0,3
%A _N. J. A. Sloane_
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