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A291943 a(0)=0; for n>0, a(n) = (2n)-th digit after the decimal point in the decimal expansion of 1/(2n+1).

%I A291943 #46 Mar 09 2018 09:12:13
%S A291943 0,3,0,7,1,9,3,6,7,1,4,3,0,3,1,9,3,5,7,2,9,3,2,7,8,1,3,1,1,1,9,1,3,7,
%T A291943 1,9,3,3,9,1,7,3,7,1,1,9,1,5,7,1,9,3,0,7,1,0,3,6,0,0,8,0,0,7,0,9,8,0,
%U A291943 7,1,0,9,8,4,1,9,4,4,7,0,6,3,0,7,3,5,3,4,0,1,9,0,4,5,0,9,3,0,7,1
%N A291943 a(0)=0; for n>0, a(n) = (2n)-th digit after the decimal point in the decimal expansion of 1/(2n+1).
%D A291943 John H. Conway & Richard K. Guy,  The Book of Numbers; Springer 1996.
%H A291943 Robert Israel, <a href="/A291943/b291943.txt">Table of n, a(n) for n = 0..10000</a>
%e A291943 a(3)=7 since we want the sixth decimal digit of 1/7.
%p A291943 f:= proc(n) floor(10^(2*n)/(2*n+1)) mod 10 end proc:
%p A291943 f(0):= 0:
%p A291943 map(f, [$0..100]); # _Robert Israel_, Oct 31 2017
%t A291943 f[n_] := Mod[Floor[10^(2n)/(2n +1)], 10]; f[0] = 0; Array[f, 105, 0] (* _Robert G. Wilson v_, Oct 31 2017 *)
%Y A291943 Cf. A002371, A003060, A006883, A036275, A051626, A061480, A114205, A121090, A270392.
%K A291943 nonn,base
%O A291943 0,2
%A A291943 _Marco Matosic_, Sep 06 2017
%E A291943 Edited by _N. J. A. Sloane_, Oct 30 2017
%E A291943 a(82) corrected by _Robert Israel_, Oct 31 2017