A044032 Numbers k such that 5 and 7 occur juxtaposed in the base-10 representation of k but not of k+1.

57, 75, 157, 175, 257, 275, 357, 375, 457, 475, 557, 579, 657, 675, 759, 775, 857, 875, 957, 975, 1057, 1075, 1157, 1175, 1257, 1275, 1357, 1375, 1457, 1475, 1557, 1579, 1657, 1675, 1759, 1775, 1857, 1875, 1957, 1975, 2057

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {5, 7}]>0 || SequenceCount[ IntegerDigits[n], {7, 5}]>0 , 1, 0], {n, 2100}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 04 2020 *)

Crossrefs

Sequence in context: A230956 A039429 A043252 * A104760 A106662 A087922

Adjacent sequences: A044029 A044030 A044031 * A044033 A044034 A044035

Keyword

nonn,base

Author

Clark Kimberling

Status

approved