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A297142 Numbers whose base-8 digits d(m), d(m-1),..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}. 5
1, 2, 3, 4, 5, 6, 7, 9, 18, 27, 36, 45, 54, 63, 64, 72, 73, 74, 75, 76, 77, 78, 79, 82, 91, 100, 109, 118, 127, 128, 137, 144, 145, 146, 147, 148, 149, 150, 151, 155, 164, 173, 182, 191, 192, 201, 210, 216, 217, 218, 219, 220, 221, 222, 223, 228, 237, 246 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

These numbers comprise the complement of the set of numbers in the union of A297140 and A297141.

Differs from A044819 first for 513 = 1001_8, which has two consecutive equal digits and is in this sequence, but has two runs of equal length (1), and is not in A044819. - R. J. Mathar, Jan 17 2018

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

Base-8 digits of 5000: 1,1,6,1,0, so that 5000 is in the sequence.

MAPLE

read("transforms") :

isA297142 := proc(n)

    local dgs, ud;

    dgs := convert(n, base, 8) ;

    if nops(dgs) < 2 then

        return true;

    end if;

    if 0 in DIFF(dgs) then

        true;

    else

        false;

    end if;

end proc:

for n from 1 to 300 do

    if isA297142(n) then

        printf("%d, ", n) ;

    end if;

end do: # R. J. Mathar, Jan 18 2018

MATHEMATICA

a[n_, b_] := Sign[Differences[IntegerDigits[n, b]]]; z = 300;

b = 8; t = Table[a[n, b], {n, 1, 10*z}];

u = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == 1 &]   (* A297140 *)

v = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == -1 &]  (* A297141 *)

Complement[Range[z], Union[u, v]]  (* A297142 *)

CROSSREFS

Cf. A297140, A297142.

Sequence in context: A083376 A044957 A044819 * A048305 A043711 A296706

Adjacent sequences:  A297139 A297140 A297141 * A297143 A297144 A297145

KEYWORD

nonn,easy,base

AUTHOR

Clark Kimberling, Jan 15 2018

STATUS

approved

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Last modified January 20 07:59 EST 2020. Contains 331081 sequences. (Running on oeis4.)