A060979 |First digit - second digit + third digit - fourth digit ...| = 11.

209, 308, 319, 407, 418, 429, 506, 517, 528, 539, 605, 616, 627, 638, 649, 704, 715, 726, 737, 748, 759, 803, 814, 825, 836, 847, 858, 869, 902, 913, 924, 935, 946, 957, 968, 979, 1309, 1408, 1419, 1507, 1518, 1529, 1606, 1617, 1628, 1639, 1705, 1716

Offset: 1

Author

Robert G. Wilson v, May 10 2001

Keywords

• base
• nonn
• easy

Comments

Note that all terms are divisible by eleven.

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A008593, A060978-A060980, A060982, A061470-A061479, A061870-A061882.

Cf. A135499.

Programs

Haskell

a060979 n = a060979_list !! (n-1)
a060979_list = filter (\x -> let digs = map (read . return) $ show x in
                             evens digs /= odds digs) [11, 22 ..]
   where evens [] = 0; evens [x] = x; evens (x:_:xs) = x + evens xs
         odds [] = 0; odds [x] = 0; odds (_:x:xs) = x + odds xs
-- Reinhard Zumkeller, Jul 05 2014

Maple

filter:= proc(n) local L,i;
  L:= convert(n,base,10);
  abs(add(L[i]*(-1)^i,i=1..nops(L))) = 11
end proc:
select(filter, [$1..1000] *~ 11); # Robert Israel, Jun 02 2023

Mathematica

Do[ a = IntegerDigits[ n ]; l = Length[ a ]; e = o = {}; Do[ o = Append[ o, a[ [ 2k - 1 ] ] ], {k, 1, l/2 + .5} ]; Do[ e = Append[ e, a[ [ 2k ] ] ], {k, 1, l/2} ]; If[ Abs[ Apply[ Plus, o ] - Apply[ Plus, e ] ] == 11, Print[ n ] ], {n, 1, 2000} ]
d11Q[n_]:=Module[{idn=IntegerDigits[n]},Abs[Total[Table[(-1)^(i+1) idn[[i]],{i,Length[idn]}]]]==11]; Select[Range[1800],d11Q] (* Harvey P. Dale, Aug 26 2012 *)

Extensions

Erroneous comment deleted by Robert Israel, Jun 02 2023