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

1,2

Comments

There are no terms >= 2^12 because 2^24-1 is the largest eight-digit octal number.

Links

Table of n, a(n) for n=1..70.

Example

110 is in the sequence because 110^2 = 12100 = 27504_8 and no octal digit occurs more than once.

Mathematica

Select[Range[2^12], DuplicateFreeQ[IntegerDigits[#^2, 8]] &] (* Michael De Vlieger, Oct 12 2024 *)

Prog

(Python)
for k in range(1, 2**12):
    octal = format(k**2, "o")
    if len(octal) == len(set(octal)): print(k, end=", ")

Crossrefs

Cf. A007094, A119509, A376898.

Sequence in context: A123643 A374125 A328845 * A240842 A168540 A115008

Adjacent sequences: A376894 A376895 A376896 * A376898 A376899 A376900

Keyword

base,fini,full,nonn

Author

Kalle Siukola, Oct 08 2024

Status

approved