

A032863


Numbers whose base8 representation Sum_{i=0..m} d(i)*8^i has d(m) > d(m1) < d(m2) > ...


3



0, 1, 2, 3, 4, 5, 6, 7, 8, 16, 17, 24, 25, 26, 32, 33, 34, 35, 40, 41, 42, 43, 44, 48, 49, 50, 51, 52, 53, 56, 57, 58, 59, 60, 61, 62, 65, 66, 67, 68, 69, 70, 71, 129, 130, 131, 132, 133, 134, 135, 138, 139, 140, 141, 142, 143, 193, 194, 195
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OFFSET

1,3


COMMENTS

Base8 digits must be strictly alternating in size: every other digit must be strictly less than its neighbor(s). Also: numbers whose base8 expansion, considered as a decimal number, is in A032865 = the base10 variant of this sequence.  M. F. Hasler, Oct 05 2018


LINKS

Table of n, a(n) for n=1..59.


EXAMPLE

From M. F. Hasler, Oct 05 2018: (Start)
The base8 representation of 7, 8, 16, 17, 24, 25, 26, 32, 33 is 7, 10, 20, 21, 30, 31, 32, 40, 41.
Numbers 61, 62, 65, 66, ..., 70, 71, 129, 130, ... have the base8 expansion 76, 77, 101, 102, ..., 106, 107, 201, 202, ... (End)


MATHEMATICA

sdQ[n_]:=Module[{s=Sign[Differences[IntegerDigits[n, 8]]]}, s==PadRight[{}, Length[s], {1, 1}]]; Select[Range[0, 700], sdQ] (* Vincenzo Librandi, Oct 06 2018 *)


PROG

(PARI) is(n)=!for(i=2, #n=digits(n, 8), (n[i1]n[i])*(1)^i>0return) \\ M. F. Hasler, Oct 05 2018


CROSSREFS

Cf. A032858, A032859, A032860, A032861, A032862, this sequence, A032864, A032865 for bases 3 to 10.
Sequence in context: A319724 A097546 A004837 * A032887 A023790 A032943
Adjacent sequences: A032860 A032861 A032862 * A032864 A032865 A032866


KEYWORD

nonn,base


AUTHOR

Clark Kimberling


EXTENSIONS

a(1) = 0 added by Vincenzo Librandi, Oct 06 2018


STATUS

approved



