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 A033001 Every run of digits of n in base 3 has length 2. 31
 4, 8, 36, 44, 72, 76, 328, 332, 396, 400, 652, 656, 684, 692, 2952, 2960, 2988, 2992, 3568, 3572, 3600, 3608, 5868, 5876, 5904, 5908, 6160, 6164, 6228, 6232, 26572, 26576, 26640, 26644, 26896, 26900, 26928, 26936, 32112, 32120 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS See A043291 for the base 2 version (which has a very simple formula), A033002 - A033014 for bases 4 through 16, A033015 - A033029 for the variants with runs of length >= 2. - M. F. Hasler, Feb 01 2014 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..250 FORMULA a(n)=4*A043307(n). - M. F. Hasler, Feb 01 2014 MATHEMATICA Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 3]]]=={2}&] (* Vincenzo Librandi, Feb 05 2014 *) PROG From M. F. Hasler, Feb 01 2014 (Start) (PARI) is_A033001(n)=!until(!n\=9, bittest(4588304, n%27)||return) (PARI) for(n=1, 9999, is_A033001(n)&&print1(n", ")) \\ (End) (PARI) a(n) = my(v=binary(n+1)); v[1]=0; for(i=2, #v, v[i]+=(v[i]>=v[i-1])); 4*fromdigits(v, 9); \\ Kevin Ryde, Mar 13 2021 CROSSREFS Sequence in context: A074736 A044829 A338086 * A269012 A149110 A354735 Adjacent sequences: A032998 A032999 A033000 * A033002 A033003 A033004 KEYWORD nonn,base AUTHOR Clark Kimberling STATUS approved

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Last modified April 25 03:15 EDT 2024. Contains 371964 sequences. (Running on oeis4.)