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Numbers in which every pair of adjacent digits are distinct.
57

%I #31 Jun 26 2023 12:45:05

%S 0,1,2,3,4,5,6,7,8,9,10,12,13,14,15,16,17,18,19,20,21,23,24,25,26,27,

%T 28,29,30,31,32,34,35,36,37,38,39,40,41,42,43,45,46,47,48,49,50,51,52,

%U 53,54,56,57,58,59,60,61,62,63,64,65,67,68,69,70,71,72,73,74,75,76,78,79,80,81,82,83,84,85,86,87,89,90,91,92,93,94,95,96,97,98,101,102,103,104,105,106,107,108,109,120,121,123,124,125,126,127,128,129

%N Numbers in which every pair of adjacent digits are distinct.

%C Superset of A010784. - _R. J. Mathar_, Oct 20 2008

%C Complement of A171901; A196368(a(n)) = 1. - _Reinhard Zumkeller_, Oct 28 2001

%H Reinhard Zumkeller, <a href="/A043096/b043096.txt">Table of n, a(n) for n = 1..10000</a>

%e 11 is the first number not in the sequence, since it has a pair of identical adjacent digits.

%p isA034096 := proc(n)

%p local dgs ;

%p dgs := convert(n,base,10) ;

%p for i from 2 to nops(dgs) do

%p if op(i,dgs) = op(i-1,dgs) then

%p return false;

%p end if;

%p end do:

%p true ;

%p end proc:

%p for n from 0 to 150 do

%p if isA034096(n) then

%p printf("%d,",n) ;

%p end if;

%p end do: # _R. J. Mathar_, Jun 26 2023

%t t={}; Do[If[!MemberQ[Differences[IntegerDigits[n]], 0], AppendTo[t,n]], {n,0,69}]; t (* _Jayanta Basu_, May 04 2013 *)

%o (Haskell)

%o import Data.List (elemIndices)

%o a043096 n = a043096_list !! n

%o a043096_list = elemIndices 1 a196368_list

%o -- _Reinhard Zumkeller_, Oct 28 2001

%o (PARI) is(n)=my(v=digits(n));for(i=2,#v,if(v[i]==v[i-1],return(0)));1 \\ _Charles R Greathouse IV_, Sep 17 2012

%o (Python)

%o def ok(n): s = str(n); return all(s[i] != s[i+1] for i in range(len(s)-1))

%o print(list(filter(ok, range(70)))) # _Michael S. Branicky_, Aug 22 2021

%Y Cf. A010784, A171901, A196368.

%K nonn,base

%O 1,3

%A _Clark Kimberling_

%E Offset corrected by _Reinhard Zumkeller_, Oct 28 2011