cp's OEIS Frontend

A215727 a(n) is the smallest m for which 3^m contains n consecutive identical digits.

%I A215727 #33 Apr 09 2020 10:32:57
%S A215727 0,11,32,33,274,538,2124,7720,22791,107187,107187,639226,5756979,
%T A215727 8885853,68353787,78927180,78927180
%N A215727 a(n) is the smallest m for which 3^m contains n consecutive identical digits.
%C A215727 3^(a(16)+1) contains exactly 16 consecutive 3's. - _Bert Dobbelaere_, Mar 20 2019
%e A215727 3^11 = 177147, which has two digits in a row.
%t A215727 A215727[n_] := Module[{m = 0 , t}, t = Table[i, {i, 0, 9}, {n}];
%t A215727 While[True, If[ContainsAny[Subsequences[IntegerDigits[3^m], {n}], t], Return[m], m++]]; m]; Table[A215727[n], {n, 1, 14}] (* _Robert Price_, Oct 16 2018 *)
%o A215727 (Python)
%o A215727 def A215727(n):
%o A215727     l, x = [str(d)*n for d in range(10)], 1
%o A215727     for m in range(10**9):
%o A215727         s = str(x)
%o A215727         for k in l:
%o A215727             if k in s:
%o A215727                 return m
%o A215727         x *= 3
%o A215727     return 'search limit reached'
%o A215727 # _Chai Wah Wu_, Dec 17 2014
%Y A215727 Cf. A215733, A045875.
%K A215727 nonn,base,more
%O A215727 1,2
%A A215727 _V. Raman_, Aug 22 2012
%E A215727 a(12) from _Chai Wah Wu_, Dec 17 2014
%E A215727 a(13)-a(14) from _Giovanni Resta_, Apr 20 2016
%E A215727 a(15) from _Bert Dobbelaere_, Mar 04 2019
%E A215727 a(16)-a(17) from _Bert Dobbelaere_, Mar 20 2019