OFFSET
1,1
MATHEMATICA
SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 7], {5, 6}]>0, 1, 0], {n, 2100}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 21 2017 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
STATUS
approved