A068861 a(1) = 1; a(n+1) is the smallest number not already in the sequence which differs from a(n) at every digit.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 21, 12, 20, 11, 22, 13, 24, 15, 23, 14, 25, 16, 27, 18, 26, 17, 28, 19, 30, 29, 31, 40, 32, 41, 33, 42, 34, 43, 35, 44, 36, 45, 37, 46, 38, 47, 39, 48, 50, 49, 51, 60, 52, 61, 53, 62, 54, 63, 55, 64, 56, 65, 57, 66, 58, 67, 59, 68, 70, 69, 71, 80

Offset

1,2

Links

Paul Tek, Table of n, a(n) for n = 1..10000

Example

11 follows 20 as the smallest number not included earlier and differing at every digit position.

Prog

(Haskell)
import Data.List (delete)
a068861 n = a068861_list !! (n-1)
a068861_list = f "x" (map show [1..]) where
   f u us = g us where
     g (v:vs)
       | and $ zipWith (/=) u v = (read v :: Int) : f v (delete v us)
       | otherwise = g vs
-- Reinhard Zumkeller, Dec 21 2013

Crossrefs

Cf. A068860, A068863.

Cf. A067581.

Sequence in context: A306361 A377903 A338840 * A341935 A256079 A216556

Adjacent sequences: A068858 A068859 A068860 * A068862 A068863 A068864

Keyword

nonn,base

Author

Amarnath Murthy, Mar 13 2002

Status

approved