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 A270027 a(n) is the smallest b >= 3 for which the base-b representation of n contains at least one 0 (or 0 if no such base exists). 12
 0, 0, 3, 4, 5, 3, 7, 4, 3, 3, 3, 3, 13, 7, 3, 4, 4, 3, 3, 3, 3, 11, 23, 3, 5, 5, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 6, 3, 43, 4, 3, 3, 3, 3, 4, 4, 3, 4, 5, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 3, 4, 4, 3, 3, 3, 3, 4, 4, 3, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS It is natural to consider this sequence starting from base 3 instead of base 2, as the latter causes most terms to be 2 (see A270026). a(n) = n if and only if n = 3 or n is in A069575. a(n) > 0 for n >= 3 since the base-n representation of n is 10. LINKS Nathan Fox, Table of n, a(n) for n = 1..10000 MATHEMATICA Table[SelectFirst[Range[3, 10^3], DigitCount[n, #, 0] > 0 &], {n, 3, 120}] (* Michael De Vlieger, Mar 10 2016, Version 10 *) PROG (PARI) a(n) = if (n < 3, 0, my(b=3); while(vecmin(digits(n, b)), b++); b); \\ Michel Marcus, Mar 10 2016 CROSSREFS Cf. A069575, A270026, A270028, A216194, A270029, A270030, A270031, A270033, A270034, A270035, A270037. Sequence in context: A090395 A168485 A276737 * A271726 A350640 A354932 Adjacent sequences: A270024 A270025 A270026 * A270028 A270029 A270030 KEYWORD nonn,base AUTHOR Nathan Fox, Mar 08 2016 STATUS approved

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Last modified April 25 11:06 EDT 2024. Contains 371967 sequences. (Running on oeis4.)