A255873 The first nonzero digit of n/7.

1, 2, 4, 5, 7, 8, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset: 1

Author

Kit Scriven, Mar 08 2015

Keywords

• nonn
• base

Examples

			The leading (most significant) digit of 22/7 in A068028 is 3, so a(22)=3.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A020806 (1/7), A068028 (22/7), A216606 (360/7).

Programs

Maple

A255873 := proc(n)
    local nshf ;
    nshf := n/7 ;
    while nshf < 1 do
        nshf := 10*nshf;
    end do;
    while nshf >= 10 do
        nshf := nshf/10;
    end do;
    floor(nshf) ;
end proc: # R. J. Mathar, May 28 2016

Mathematica

f[n_] := RealDigits[n/7, 10, 9][[1, 1]]; Array[f, 105] (* Robert G. Wilson v, Mar 08 2015 *)

PARI

a(n) = {my(x = n/7.0); if (x < 1, x *= 10); while (x >= 10, x /= 10); floor(x);} \\ Michel Marcus, Mar 12 2015