%I #26 Apr 18 2020 08:05:06
%S 0,11,50,95,125,1087,2786,2790,2796,2797,2802,2803,1040703,5547565,
%T 7761841,17876345
%N a(n) is the smallest m for which 5^m contains n consecutive identical digits.
%C a(13) > 893000. - _Chai Wah Wu_, Dec 17 2014
%o (Python)
%o def A215728(n):
%o l, x = [str(d)*n for d in range(10)], 1
%o for m in range(10**9):
%o s = str(x)
%o for k in l:
%o if k in s:
%o return m
%o x *= 5
%o return 'search limit reached'
%o # _Chai Wah Wu_, Dec 17 2014
%Y Cf. A215734, A045875.
%K nonn,base,more
%O 1,2
%A _V. Raman_, Aug 22 2012
%E a(13)-a(14) from _Giovanni Resta_, Apr 19 2016
%E a(15)-a(16) from _Bert Dobbelaere_, Feb 13 2019