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A138142 Nonnegative numbers with digits in descending order that differ exactly by 1. 2


%S 0,1,2,3,4,5,6,7,8,9,10,21,32,43,54,65,76,87,98,210,321,432,543,654,

%T 765,876,987,3210,4321,5432,6543,7654,8765,9876,43210,54321,65432,

%U 76543,87654,98765,543210,654321,765432,876543,987654

%N Nonnegative numbers with digits in descending order that differ exactly by 1.

%C This finite sequence has 55 members. The last member is 9876543210. There are 11-k members with k digits. See A052016 for primes in this sequence. All members with 3 or more digits are straight-line numbers A135643.

%e Last 10 members of this finite sequence:

%e a(45)=6543210

%e a(46)=7654321

%e a(47)=8765432

%e a(48)=9876543

%e a(49)=76543210

%e a(50)=87654321

%e a(51)=98765432

%e a(52)=876543210

%e a(53)=987654321

%e a(54)=9876543210

%t fQ[n_]:=Module[{id=IntegerDigits[n]}, n<10 || Union[Differences[id]]=={-1}]; Select[Range[0, 100000], fQ] (* _Vladimir Joseph Stephan Orlovsky_, Dec 29 2010 *)

%t Sort[Flatten[With[{t=Range[9,0,-1]},Table[FromDigits/@Partition[t,n,1],{n,10}]]]] (* _Harvey P. Dale_, Oct 31 2013 *)

%Y Cf. A052016, A135643, A138141.

%K base,easy,fini,nonn

%O 1,3

%A _Omar E. Pol_, Mar 19 2008

%E Examples corrected by _Omar E. Pol_, Dec 06 2008

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Last modified May 6 06:00 EDT 2021. Contains 343580 sequences. (Running on oeis4.)