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 A007735 #22 Aug 26 2024 04:54:45 %S A007735 1,1,1,1,2,1,3,1,3,2,5,1,6,3,2,1,4,3,9,2,3,5,11,1,10,6,9,3,14,2,5,1,5, %T A007735 4,6,3,18,9,6,2,10,3,7,5,6,11,23,1,21,10,4,6,26,9,10,3,9,14,29,2,30,5, %U A007735 3,1,6,5,33,4,11,6,35,3,9,18,10,9,15,6,39,2,27,10,41,3,4,7,14,5,11,6,6,11,5 %N A007735 Period of base 4 representation of 1/n. %H A007735 T. D. Noe, <a href="/A007735/b007735.txt">Table of n, a(n) for n=1..1000</a> %H A007735 <a href="/index/1#1overn">Index entries for sequences related to decimal expansion of 1/n</a>. %t A007735 DigitCycleLength[r_Rational, b_Integer?Positive] := MultiplicativeOrder[b, FixedPoint[ Quotient[#, GCD[#, b]] &, Denominator[r]]]; DigitCycleLength[1, b_Integer?Positive] = 1; Array[ DigitCycleLength[1/#, 4] &, 80] (* _Robert G. Wilson v_, Jun 10 2011 *) %t A007735 a[n_] := MultiplicativeOrder[4, n/2^IntegerExponent[n, 2]]; Array[a, 100] (* _Amiram Eldar_, Aug 26 2024 *) %Y A007735 Cf. A007733 (base 2), A007734 (3), A007736 (5), A007737 (6), A007738 (7), A007739 (8), A007740 (9), A007732 (10). %K A007735 nonn,base %O A007735 1,5 %A A007735 _N. J. A. Sloane_, Hal Sampson (hals(AT)easynet.com) %E A007735 More terms from _David W. Wilson_