This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A007740 #29 Aug 26 2024 04:56:02 %S A007740 1,1,1,1,2,1,3,1,1,2,5,1,3,3,2,2,8,1,9,2,3,5,11,1,10,3,1,3,14,2,15,4, %T A007740 5,8,6,1,9,9,3,2,4,3,21,5,2,11,23,2,21,10,8,3,26,1,10,3,9,14,29,2,5, %U A007740 15,3,8,6,5,11,8,11,6,35,1,6,9,10,9,15,3,39,2,1,4,41,3,8,21,14,5,44,2,3,11,15,23 %N A007740 Period of repeating digits of 1/n in base 9. %C A007740 Not multiplicative. Smallest counterexample a(5) = a(16) = 2, but a(80) = 2. - _David W. Wilson_, Jun 09 2005 %H A007740 T. D. Noe, <a href="/A007740/b007740.txt">Table of n, a(n) for n=1..1000</a> %H A007740 <a href="/index/1#1overn">Index entries for sequences related to decimal expansion of 1/n</a>. %t A007740 DigitCycleLength[r_Rational, b_Integer?Positive] := MultiplicativeOrder[b, FixedPoint[ Quotient[#, GCD[#, b]] &, Denominator[r]]]; DigitCycleLength[1, b_Integer?Positive] = 1; Array[ DigitCycleLength[1/#, 9] &, 80] (* _Robert G. Wilson v_, Jun 10 2011 *) %t A007740 a[n_] := MultiplicativeOrder[9, n/3^IntegerExponent[n, 3]]; Array[a, 100] (* _Amiram Eldar_, Aug 26 2024 *) %Y A007740 Cf. A007733 (base 2), A007734 (3), A007735 (4), A007736 (5), A007737 (6), A007738 (7), A007739 (8), A007732 (10). %K A007740 nonn,base %O A007740 1,5 %A A007740 _N. J. A. Sloane_, Hal Sampson (hals(AT)easynet.com)