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%I #27 Apr 29 2020 10:01:29
%S 0,3,0,142857,9,76923,588235294117647,52631578947368421,
%T 434782608695652173913,344827586206896551724137931,32258064516129,27,
%U 2439,23255813953488372093,212765957446808510638297872340425531914893617
%N Periodic part of decimal expansion of reciprocal of n-th prime (leading 0's omitted).
%H T. D. Noe, <a href="/A060282/b060282.txt">Table of n, a(n) for n=1..100</a>
%F a(n) = floor(10^A002371(n)/prime(n)).
%F a(n) = 0 if and only if n = 1 or 3, corresponding to the primes 2 and 5, which are factors of 10. - _Alonso del Arte_, Apr 03 2020
%F ceiling(log_10(a(n))) = prime(n) - 1 if prime(n) is a full reptend prime (A001913). - _Alonso del Arte_, Apr 14 2020
%e 1/7 = 0.142857142..., so a(4) = 142857.
%e 1/11 = 0.09090909..., so a(5) = 9.
%t primePer[1] = primePer[3] = 0; primePer[n_] := FromDigits[(d = RealDigits[1/Prime[n]])[[1, 1]]] * 10^d[[2]]; Array[ primePer, 15] (* _Amiram Eldar_, Apr 28 2020 *)
%o (PARI) f(n)=if(n<4,n==2,znorder(Mod(10, prime(n)))) \\ A002371
%o for(n=1,100,print1(floor(10^f(n)/prime(n)),","))
%Y Cf. A002371, A036275, A060283, A060251, A036275, A001913.
%K nonn,easy,base
%O 1,2
%A _N. J. A. Sloane_, Mar 30 2001
%E More terms from _Klaus Brockhaus_, Mar 30 2001
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