

A023802


Xenodromes: all digits in base 7 are different.


2



0, 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 51, 52, 53, 54, 55, 63, 66, 67, 68, 69, 70, 72, 74, 75, 76, 77, 79, 80, 82, 83, 84, 86, 87, 88, 90
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OFFSET

1,3


LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..11743 (full sequence)


EXAMPLE

4146 in base 7 is 15042. Since no two digits of the base 7 representation are the same, 4146 is in the sequence.
4147 in base 7 is 15043. Since no two digits of the base 7 representation are the same, 4147 is in the sequence.
4148 in base 7 is 15044. Since the digit 4 appears twice in the base 7 representation, 4148 is not in the sequence.


MATHEMATICA

Select[Range[0, 97], Max[DigitCount[#, 7]] == 1 &] (* Alonso del Arte, Feb 09 2019 *)


PROG

(PARI) isok(n) = my(d=digits(n, 7)); #d == #Set(d); \\ Michel Marcus, Feb 09 2019


CROSSREFS

Cf. A023798  A023810.
Cf. A007093 (numbers in base 7).
Cf. A044956 (includes a subset of the complement of this sequence).
Sequence in context: A187320 A255805 A043093 * A007915 A004709 A048107
Adjacent sequences: A023799 A023800 A023801 * A023803 A023804 A023805


KEYWORD

nonn,base,fini,full,easy


AUTHOR

Olivier Gérard


STATUS

approved



