A078453 Numbers in which all the digits are coprime to each other.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 25, 27, 29, 31, 32, 34, 35, 37, 38, 41, 43, 45, 47, 49, 51, 52, 53, 54, 56, 57, 58, 59, 61, 65, 67, 71, 72, 73, 74, 75, 76, 78, 79, 81, 83, 85, 87, 89, 91, 92, 94, 95, 97, 98

Offset

1,3

Comments

A term can have at most 4 digits that are not 1, but can have any number of 1's. - Robert Israel, Apr 21 2026

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

filter:= proc(n) local L, d, i, j;
  L:= convert(n, base, 10); d:= nops(L);
  `and`(seq(seq(igcd(L[i], L[j])=1, j=i+1..d), i=1..d))
end proc:
select(filter, [$0..200]); # Robert Israel, Apr 21 2026

Mathematica

Join[Range[0, 9], Select[Range[10, 98], GCD@@IntegerDigits[#]==1 &]] (* Stefano Spezia, Dec 23 2022 *)

Prog

(Python)
from math import gcd
from functools import reduce
def ok(n):
    d = list(map(int, str(n)))
    return len(d) == 1 or reduce(gcd, d) == 1
print([k for k in range(100) if ok(k)]) # Michael S. Branicky, Dec 23 2022

Crossrefs

Cf. A069715.

Sequence in context: A084981 A326880 A359077 * A052425 A272074 A246097

Adjacent sequences: A078450 A078451 A078452 * A078454 A078455 A078456

Keyword

base,easy,nonn

Author

Amarnath Murthy, Nov 28 2002

Status

approved