cp's OEIS Frontend

A195138 First digit to appear n times in the decimal expansion of e.

%I A195138 #43 Apr 02 2021 22:26:30
%S A195138 2,2,8,8,2,2,2,2,9,7,7,7,7,7,7,7,7,7,7,2,2,2,2,2,2,2,3,9,9,2,7,4,4,7,
%T A195138 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,9,9,9,9,
%U A195138 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9
%N A195138 First digit to appear n times in the decimal expansion of e.
%C A195138 The digits 0 and 5 do not appear among the first 30000 terms. When do they first appear? - _Jianing Song_, Apr 01 2021
%H A195138 Alois P. Heinz, <a href="/A195138/b195138.txt">Table of n, a(n) for n = 1..10000</a>
%e A195138 From _Michael De Vlieger_, Sep 10 2017: (Start)
%e A195138 a(n) is the first decimal digit of e that first appears n times when e is expanded to the -m place:
%e A195138    n  a(n)  m
%e A195138    1   2    0
%e A195138    2   2    4
%e A195138    3   8    7
%e A195138    4   8    9
%e A195138    5   2   22
%e A195138    6   2   30
%e A195138    7   2   33
%e A195138    8   2   40
%e A195138    9   9   58
%e A195138   10   7   63
%e A195138   11   7   64
%e A195138   12   7   68
%e A195138   13   7   78
%e A195138   14   7   83
%e A195138   15   7   89
%e A195138   16   7   99
%e A195138 (End)
%t A195138 With[{e = First@ RealDigits[N[E, 10^4]]}, Function[t, -1 + Map[FirstPosition[t, #] &, Range@ Max@ t][[All, -1]]]@ Table[BinCounts[Take[e, n], {0, 10, 1}], {n, 10^3}]] (* _Michael De Vlieger_, Sep 10 2017 *)
%Y A195138 Cf. A001113, A195844, A277270, A290643, A290644.
%Y A195138 Cf. A096567, A195139, A195141, A280811, A341438.
%K A195138 nonn,base
%O A195138 1,1
%A A195138 _Omar E. Pol_, Oct 22 2011
%E A195138 More terms from _D. S. McNeil_, Oct 22 2011