A043221 Numbers k such that 0 and 6 occur juxtaposed in the base-10 representation of k but not of k-1.

60, 106, 160, 206, 260, 306, 360, 406, 460, 506, 560, 600, 660, 706, 760, 806, 860, 906, 960, 1006, 1060, 1106, 1160, 1206, 1260, 1306, 1360, 1406, 1460, 1506, 1560, 1600, 1660, 1706, 1760, 1806, 1860, 1906, 1960, 2006, 2060

Offset

1,1

Links

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

Example

600 is in the sequence because its base-10 representation includes the digits 0 and 6, but 599 includes neither.
606 is not in the sequence, because, even though its base-10 representation does include the digits 0 and 6, so does 605.

Maple

filter:= proc(n)
  local L, P;
  L:= convert(n-1, base, 10);
  if member({0, 6}, {seq({L[i], L[i+1]}, i=1..nops(L)-1)}) then return false fi;
  L:= convert(n, base, 10);
  member({0, 6}, {seq({L[i], L[i+1]}, i=1..nops(L)-1)});
end proc:
select(filter, [$1..10^4]); # Robert Israel, Nov 18 2014

Mathematica

Transpose[SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {0, 6}]>0||SequenceCount[IntegerDigits[n], {6, 0}]>0, 1, 0], {n, 2200}], {0, 1}]][[2]] (* The program uses the SequencePosition and SequenceCount functions from Mathematica version 10 *) (* Harvey P. Dale, Aug 01 2016 *)

Crossrefs

Sequence in context: A048934 A097714 A272515 * A039398 A044001 A258700

Adjacent sequences: A043218 A043219 A043220 * A043222 A043223 A043224

Keyword

nonn,base

Author

Clark Kimberling

Status

approved