A376897 Positive numbers k such that all the digits in the octal expansion of k^2 are distinct.
1, 2, 4, 5, 7, 13, 14, 15, 18, 20, 21, 28, 30, 37, 39, 43, 44, 45, 53, 55, 63, 78, 84, 103, 110, 113, 117, 127, 149, 155, 156, 161, 162, 172, 173, 174, 175, 179, 220, 236, 242, 270, 286, 293, 299, 301, 340, 343, 350, 356, 361, 395, 407, 412, 425, 439, 461, 475, 499, 674, 819, 1001, 1211, 1230, 1244, 1323, 1764, 2450, 2751, 3213
Offset: 1
Examples
110 is in the sequence because 110^2 = 12100 = 27504_8 and no octal digit occurs more than once.
Programs
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Mathematica
Select[Range[2^12], DuplicateFreeQ[IntegerDigits[#^2, 8]] &] (* Michael De Vlieger, Oct 12 2024 *)
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Python
for k in range(1, 2**12): octal = format(k**2, "o") if len(octal) == len(set(octal)): print(k, end=",")
Comments