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A107780 a(1)=9, a(n) = smallest integer not previously used which contains a digit from a(n-1). 10
9, 19, 1, 10, 0, 20, 2, 12, 11, 13, 3, 23, 21, 14, 4, 24, 22, 25, 5, 15, 16, 6, 26, 27, 7, 17, 18, 8, 28, 29, 32, 30, 31, 33, 34, 35, 36, 37, 38, 39, 43, 40, 41, 42, 44, 45, 46, 47, 48, 49, 54, 50, 51, 52, 53, 55, 56, 57, 58, 59, 65, 60, 61, 62, 63, 64, 66, 67, 68, 69, 76, 70 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

S:= [$0..100]:

Res:= 9: S:= subs(9=NULL, S):

digs:= {9}:

while S <> [] do

  found:= false;

  for i from 1 to nops(S) while not found do

    ndigs:= convert(convert(S[i], base, 10), set);

    if ndigs intersect digs <> {} then

      found:= true;

      Res:=Res, S[i];

      S:= subsop(i=NULL, S);

      digs:= ndigs;

    fi

  od;

  if not found then break fi;

od:

Res; # Robert Israel, Jan 22 2020

MATHEMATICA

f[l_] := Block[{c = 0}, While[ MemberQ[l, c] || Intersection @@ IntegerDigits /@{Last[l], c}=={}, c++ ]; Return[Append[l, c]]]; Nest[f, {9}, 70] (* Ray Chandler, Jul 19 2005 *)

CROSSREFS

Cf. A107353 a(1)=0, A107772 a(1)=1, A107773 a(1)=2, A107774 a(1)=3, A107775 a(1)=4, A107776 a(1)=5, A107777 a(1)=6, A107778 a(1)=7, A107779 a(1)=8, A107781 a(1)=10.

Sequence in context: A134115 A071587 A061750 * A288392 A157140 A244538

Adjacent sequences:  A107777 A107778 A107779 * A107781 A107782 A107783

KEYWORD

base,nonn

AUTHOR

Eric Angelini & Zak Seidov, May 24 2005

STATUS

approved

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Last modified April 10 11:15 EDT 2021. Contains 342845 sequences. (Running on oeis4.)