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

1,2

Links

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

Prog

(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

Crossrefs

Cf. A054659, A067581, A276633, A276512.

Sequence in context: A308540 A179310 A114806 * A276766 A331215 A039229

Adjacent sequences: A239661 A239662 A239663 * A239665 A239666 A239667

Keyword

nonn,base

Author

Reinhard Zumkeller, Mar 23 2014

Status

approved