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A285056 a(n) = the first positive integer, not ending in zero, whose cube has a substring of exactly n identical digits.

%I A285056 #16 Apr 10 2017 23:42:39
%S A285056 1,11,126,753,1923,32183,134708,1487139,23908603,215443469,106917811,
%T A285056 15056809703,27354803113,681048619195,361160395301
%N A285056 a(n) = the first positive integer, not ending in zero, whose cube has a substring of exactly n identical digits.
%e A285056 a(3) = 126, as 126^3 = 2000376 contains a digit (0) repeated n (3) times.
%t A285056 a[n_] := Block[{k=1}, While[Mod[k, 10] == 0 || ! MemberQ[Length /@ Split[ IntegerDigits[ k^3]], n], k++]; k]; Array[a, 8] (* _Giovanni Resta_, Apr 10 2017 *)
%o A285056 (Python) import collections
%o A285056 import re
%o A285056 cur = 1
%o A285056 def repeat( num , reps ):
%o A285056     r = str(num)
%o A285056     n = 1
%o A285056     while n < reps:
%o A285056         r += str(num)
%o A285056         n += 1
%o A285056     return r;
%o A285056 while True:
%o A285056     k = 0
%o A285056     while k < 10:
%o A285056         rep = repeat(k,9)
%o A285056         while re.search(rep, str(cur**3)) != None:
%o A285056             if re.search(rep + str(k), str(cur**3)) == None:
%o A285056                 print(str(cur) + ", " + str(cur**3))
%o A285056                 rep += str(k)
%o A285056             else:
%o A285056                 rep += str(k)
%o A285056         k += 1
%o A285056     cur += 1
%o A285056     if cur % 10 == 0:
%o A285056         cur += 1 #note: this will display all cubes with a substring of 9 repeated digits. To change this to n repeats, replace repeat(k,9) with repeat(k,n).
%Y A285056 Cf. A167712.
%K A285056 nonn,base,more
%O A285056 1,2
%A A285056 _Jason Wang_, Apr 08 2017
%E A285056 a(10)-a(15) from _Giovanni Resta_, Apr 10 2017