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A033001
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Every run of digits of n in base 3 has length 2.
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31
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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
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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MATHEMATICA
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Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 3]]]=={2}&] (* Vincenzo Librandi, Feb 05 2014 *)
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PROG
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(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
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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