A239664 a(n) = 1, a(n+1) = smallest number not occurring earlier, having with a(n) neither a common digit nor a common divisor.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 23, 11, 20, 13, 22, 15, 26, 17, 24, 19, 25, 14, 27, 16, 29, 18, 35, 12, 37, 21, 34, 55, 28, 31, 40, 33, 41, 30, 47, 32, 45, 38, 49, 36, 59, 42, 53, 44, 39, 46, 51, 43, 50, 61, 48, 65, 71, 52, 63, 58, 67, 54, 73, 56, 79, 60, 77

Offset: 1

Author

Reinhard Zumkeller, Mar 23 2014

Keywords

• nonn
• base

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A054659, A067581, A276633, A276512.

Programs

Haskell

import Data.List (delete, intersect); import Data.Function (on)
a239664 n = a239664_list !! (n-1)
a239664_list = 1 : f 1 [2..] where
   f v ws = g ws where
     g (x:xs) = if gcd v x == 1 && ((intersect `on` show) v x == "")
                   then x : f x (delete x ws) else g xs

PARI

{u=[]; a=1; for(n=1,99, print1(a","); u=setunion(u,[a]); while(#u>1&&u[2]==u[1]+1,u=u[^1]); for(k=u[1]+1,9e9, setsearch(u,k)&&next;gcd(k,a)>1&&next; #setintersect(Set(digits(a)),Set(digits(k)))&&next; a=k; next(2)));a} \\ M. F. Hasler, Sep 17 2016