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 A178905 Numbers without 3 consecutive equal digits in any base b >= 2. 2
 0, 1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 18, 19, 20, 22, 25, 36, 37, 38, 44, 45, 50, 51, 52, 74, 75, 76, 77, 89, 90, 100, 101, 102, 105, 109, 147, 150, 153, 154, 165, 166, 173, 178, 179, 180, 181, 204, 205, 210, 212, 214, 217, 293, 294, 299, 300, 301, 306, 308, 309, 329 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Michael S. Branicky, Table of n, a(n) for n = 1..10000 MATHEMATICA Prepend[Cases[Range[329], n_ /; NoneTrue[Range[2, (Sqrt[4 n - 3] - 1)/2], MatchQ[IntegerDigits[n, #], {___, d_, d_, d_, ___}] &]], 0] (* Vladimir Reshetnikov, Mar 20 2022 *) PROG (Python) from sympy.ntheory.digits import digits def three_in_a_row(s): return any(s[i] == s[i+1] == s[i+2] for i in range(len(s) - 2)) def ok(n): if n < 7: return True b = 2 d = digits(n, b)[1:] while len(d) >= 3: if three_in_a_row(d): return False b += 1 d = digits(n, b)[1:] return True print([k for k in range(331) if ok(k)]) # Michael S. Branicky, Mar 27 2022 CROSSREFS Cf. A063037. Sequence in context: A157189 A136250 A175585 * A349955 A168009 A134697 Adjacent sequences: A178902 A178903 A178904 * A178906 A178907 A178908 KEYWORD base,nonn AUTHOR Joonas Pohjonen, Jun 22 2010 STATUS approved

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Last modified May 29 21:17 EDT 2023. Contains 363042 sequences. (Running on oeis4.)