A043167 Numbers k such that 2 and 5 occur juxtaposed in the base-8 representation of k but not of k-1.

21, 42, 85, 106, 149, 168, 213, 234, 277, 298, 336, 362, 405, 426, 469, 490, 533, 554, 597, 618, 661, 680, 725, 746, 789, 810, 848, 874, 917, 938, 981, 1002, 1045, 1066, 1109, 1130, 1173, 1192, 1237, 1258, 1301, 1322, 1344

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Links

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

Crossrefs

Cf. A007094.

Programs

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n,8],{2,5}]>0 || SequenceCount[ IntegerDigits[ n,8],{5,2}]>0,1,0],{n,1500}],{0,1}][[;;,2]] (* Harvey P. Dale, Jun 02 2024 *)