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 A109691 Smallest 5th power that contains exactly n occurrences of the string n. 2
 1, 1, 248832, 6436343, 45435424, 15575653771875, 616132666368, 778890712975487707, 6648881538818884375, 99900039992000799968, 10610441011074322410255643277715061010710106439101, 11311111984777108548801111731222111251108343 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(11) assumes occurrences can overlap (cf. A109689). - Michael S. Branicky, Dec 21 2020 LINKS Table of n, a(n) for n=0..11. EXAMPLE a(2)=248832 since this is the first 5th power that contains exactly two 2's. PROG (Python) def count_overlaps(subs, s): c = i = 0 while i != -1: i = s.find(subs, i) if i != -1: c += 1; i += 1 return c def a(n, POW=5): # call with 4, 3 for A109690, A109689, resp. strn = str(n) k = int((10**(len(set(strn))*n-1))**(1/POW)) # len(strn) for no overlaps while True: # if str(pow(k, POW)).count(strn) == n: break # use this for no overlaps if count_overlaps(strn, str(pow(k, POW))) == n: break k += 1 return k**POW print([a(n) for n in range(10)]) # Michael S. Branicky, Dec 21 2020 CROSSREFS Cf. A109689 (cubes), A109690 (4th powers). Sequence in context: A268842 A223238 A017405 * A017525 A223326 A250516 Adjacent sequences: A109688 A109689 A109690 * A109692 A109693 A109694 KEYWORD base,more,nonn AUTHOR Erich Friedman, Aug 07 2005 EXTENSIONS a(10)-a(11) from Michael S. Branicky, Dec 21 2020 STATUS approved

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Last modified September 16 08:45 EDT 2024. Contains 375959 sequences. (Running on oeis4.)