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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. 1
 1, 11, 126, 753, 1923, 32183, 134708, 1487139, 23908603, 215443469, 106917811, 15056809703, 27354803113, 681048619195, 361160395301 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS EXAMPLE a(3) = 126, as 126^3 = 2000376 contains a digit (0) repeated n (3) times. MATHEMATICA 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 *) PROG (Python) import collections import re cur = 1 def repeat( num , reps ):     r = str(num)     n = 1     while n < reps:         r += str(num)         n += 1     return r; while True:     k = 0     while k < 10:         rep = repeat(k, 9)         while re.search(rep, str(cur**3)) != None:             if re.search(rep + str(k), str(cur**3)) == None:                 print(str(cur) + ", " + str(cur**3))                 rep += str(k)             else:                 rep += str(k)         k += 1     cur += 1     if cur % 10 == 0:         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). CROSSREFS Cf. A167712. Sequence in context: A240335 A076483 A209901 * A015597 A296732 A156970 Adjacent sequences:  A285053 A285054 A285055 * A285057 A285058 A285059 KEYWORD nonn,base,more AUTHOR Jason Wang, Apr 08 2017 EXTENSIONS a(10)-a(15) from Giovanni Resta, Apr 10 2017 STATUS approved

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Last modified September 18 07:39 EDT 2020. Contains 337166 sequences. (Running on oeis4.)