A061116 Numbers coprime to each of their decimal digits.

11, 13, 17, 19, 21, 23, 27, 29, 31, 37, 41, 43, 47, 49, 51, 53, 57, 59, 61, 67, 71, 73, 79, 81, 83, 87, 89, 91, 97, 111, 113, 117, 119, 121, 127, 131, 133, 137, 139, 141, 143, 149, 151, 157, 161, 163, 167, 169, 171, 173, 177, 179, 181, 187, 191, 193, 197, 199, 211

Offset: 1

Author

Amarnath Murthy, Apr 21 2001

Keywords

• nonn
• base

Comments

A138707(a(n)) = 1; subsequence of A138708. - Reinhard Zumkeller, Mar 26 2008

Examples

			27 is a member as 2 and 7 both are coprime to 27. 53 is a member as 5 and 3 both are coprime to 53.
		

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..10000
• Index entries for 10-automatic sequences.

Crossrefs

Cf. A138707, A138708.

Programs

Maple

for n from 2 to 500 do it1 := convert(n, base, 10): flag := 1: for k from 1 to nops(it1) do if igcd(n, it1[k])<>1 then flag := 0 fi: od: if flag=1 then printf(`%d,`,n) fi: od:

Mathematica

Select[Range[11, 191, 2], CoprimeQ[Product[i, {i, IntegerDigits[#]}], #] &] (* Arkadiusz Wesolowski, May 19 2012 *)

Python

from math import gcd
def ok(n): return n > 1 and all(gcd(n, int(d)) == 1 for d in str(n))
print([k for k in range(212) if ok(k)]) # Michael S. Branicky, Nov 13 2021

Extensions

More terms from James Sellers, Apr 23 2001