OFFSET
1,1
COMMENTS
LINKS
Ray Chandler, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 7 because A000040(4) Period of decimal expansion of 1/7 = 6 = 2*3, a semiprime.
a(2) = 13 because A000040(6) = 6 = 2*3.
a(3) = 23 because A000040(9) = 22 = 2*11.
a(4) = 31 because A000040(11) = 15 = 3*5.
a(5) = 43 because A000040(14) = 21 = 3*7.
a(6) = 47 because A000040(15) = 46 = 2*23.
a(7) = 59 because A000040(17) = 58 = 2*29.
MATHEMATICA
fQ[p_] := Plus @@ Last /@ FactorInteger@Length@RealDigits[1/p][[1, 1]] == 2;; lst = {}; Do[ p = Prime@n; If[ fQ@p, AppendTo[lst, p]], {n, 230}] (* Robert G. Wilson v *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Jonathan Vos Post, May 12 2007
STATUS
approved