A043152 Numbers k such that 0 and 1 occur juxtaposed in the base-8 representation of k but not of k-1.

8, 64, 129, 136, 193, 200, 257, 264, 321, 328, 385, 392, 449, 456, 512, 641, 648, 705, 712, 769, 776, 833, 840, 897, 904, 961, 968, 1025, 1032, 1088, 1153, 1160, 1217, 1224, 1281, 1288, 1345, 1352, 1409, 1416, 1473, 1480, 1537

Offset

1,1

Links

Table of n, a(n) for n=1..43.

Mathematica

n01Q[n_]:=MemberQ[Sort/@Partition[IntegerDigits[n, 8], 2, 1], {0, 1}]; Select[Range[1600], n01Q[#]&&!n01Q[#-1]&] (* Harvey P. Dale, Oct 25 2011 *)

Prog

(Python)
def ok(n):
    on, onm1 = oct(n)[2:], oct(n-1)[2:]
    return ("01" in on or "10" in on) and not ("01" in onm1 or "10" in onm1)
print(list(filter(ok, range(1, 1538)))) # Michael S. Branicky, Aug 22 2021

Crossrefs

Cf. A007094.

Sequence in context: A209990 A235425 A255932 * A044195 A153808 A207601

Adjacent sequences: A043149 A043150 A043151 * A043153 A043154 A043155

Keyword

nonn,base

Author

Clark Kimberling

Status

approved