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A155150
Numbers k such that k^4 has exactly 4 distinct decimal digits.
5
6, 7, 8, 15, 19, 21, 24, 27, 28, 36, 39, 40, 42, 46, 50, 52, 57, 64, 67, 69, 70, 80, 85, 88, 90, 101, 110, 131, 150, 160, 183, 190, 202, 203, 340, 400, 433, 500, 570, 670, 700, 800, 843, 850, 900, 1001, 1010, 1100, 1171, 1500, 1600, 1900, 2673, 2868, 3400, 4000
OFFSET
1,1
LINKS
MATHEMATICA
ddd4Q[n_]:=Count[DigitCount[n^4], _?(#>0&)]==4; Select[Range[5000], ddd4Q] (* Harvey P. Dale, Nov 10 2012 *)
Select[Range[4000], Length[Union[IntegerDigits[#^4]]]==4&] (* Vincenzo Librandi, Nov 07 2014 *)
PROG
(Python)
A155150_list, m = [], [24, -36, 14, -1, 0]
for n in range(1, 10**3+1):
for i in range(4):
m[i+1] += m[i]
if len(set(str(m[-1]))) == 4:
A155150_list.append(n) # Chai Wah Wu, Nov 05 2014
(Magma) [n: n in [0..4000] | #Set(Intseq(n^4)) eq 4]; // Vincenzo Librandi, Nov 07 2014
CROSSREFS
KEYWORD
nonn,base,changed
AUTHOR
Dmitry Kamenetsky, Jan 21 2009
EXTENSIONS
Edited by Charles R Greathouse IV, Aug 02 2010
STATUS
approved