Search: id:A098680 Results 1-1 of 1 results found. %I A098680 %S A098680 2393,15497,18149,18617,20021,25819,26183,26339,29303,39937,42953,48491, %T A098680 52313,53327,57331,58189,59021,65183,81953,82499,87491,91703,98047, %U A098680 102233,104287,109097,111229,119419,129793,131171,143287,143833,162007 %N A098680 Primes p for which the period of reciprocal = (p-1)/13. %H A098680 Index entries for sequences related to decimal expansion of 1/n %t A098680 f[n_Integer] := Block[{ds = Divisors[n - 1]}, (n - 1)/Take[ ds, Position[ PowerMod[ 10, ds, n], 1] [[1, 1]]] [[ -1]]]; Select[ Prime[ Range[4, 15000]], f[ # ] == 13 &] %Y A098680 Sequence in context: A020394 A020428 A100974 this_sequence A115931 A108055 A043420 %Y A098680 Adjacent sequences: A098677 A098678 A098679 this_sequence A098681 A098682 A098683 %K A098680 nonn %O A098680 1,1 %A A098680 Robert G. Wilson v (rgwv(AT)rgwv.com), Sep 15 2004 Search completed in 0.001 seconds