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

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, 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, 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

Offset

0,2

References

John H. Conway & Richard K. Guy, The Book of Numbers; Springer 1996.

Links

Robert Israel, Table of n, a(n) for n = 0..10000

Example

a(3)=7 since we want the sixth decimal digit of 1/7.

Maple

f:= proc(n) floor(10^(2*n)/(2*n+1)) mod 10 end proc:
f(0):= 0:
map(f, [$0..100]); # Robert Israel, Oct 31 2017

Mathematica

f[n_] := Mod[Floor[10^(2n)/(2n +1)], 10]; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Oct 31 2017 *)

Crossrefs

Cf. A002371, A003060, A006883, A036275, A051626, A061480, A114205, A121090, A270392.

Sequence in context: A011080 A021769 A200119 * A203622 A201571 A010600

Adjacent sequences: A291940 A291941 A291942 * A291944 A291945 A291946

Keyword

nonn,base

Author

Marco Matosic, Sep 06 2017

Extensions

Edited by N. J. A. Sloane, Oct 30 2017

a(82) corrected by Robert Israel, Oct 31 2017

Status

approved