

A060262


a(n) is the smallest x such that p(x), p(x+1), ..., p(x+n1) all have 10 as a primitive root, but p(x1) and p(x+n) do not, where p(n)=A000040(n) is the nth prime.


3



4, 17, 55, 7, 93, 754, 2611, 31092, 55207, 301252, 955428, 805428
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OFFSET

1,1


COMMENTS

A prime p has 10 as a primitive root iff the length of the period of the decimal expansion of 1/p is p1.


LINKS

Table of n, a(n) for n=1..12.


MATHEMATICA

test[p_] := MultiplicativeOrder[10, p]===p1; For[n=1, n<100, n++, a[n]=0]; v=4; While[True, For[n=1, test[Prime[v+n]], n++, Null]; If[a[n]==0, a[n]=v; Print["a(", n, ") = ", v]]; For[v+=n+1, !test[Prime[v]], v++, Null]]


CROSSREFS

Cf. A001913, A002371, A060259, A060260, A060261.
Sequence in context: A092091 A046995 A001585 * A157492 A108140 A213577
Adjacent sequences: A060259 A060260 A060261 * A060263 A060264 A060265


KEYWORD

nonn,more


AUTHOR

Jeff Burch, Mar 23 2001


EXTENSIONS

Edited by Dean Hickerson, Jun 17 2002


STATUS

approved



