A044219 Numbers n such that string 4,0 occurs in the base 8 representation of n but not of n-1.

32, 96, 160, 224, 256, 288, 352, 416, 480, 544, 608, 672, 736, 768, 800, 864, 928, 992, 1056, 1120, 1184, 1248, 1280, 1312, 1376, 1440, 1504, 1568, 1632, 1696, 1760, 1792, 1824, 1888, 1952, 2016, 2048, 2144, 2208, 2272, 2304

Offset

1,1

Links

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

Maple

# return true if s is a sublist of L
subL := proc(L::list, s::list)
    local ldiff, ls, i;
    ls := nops(s) ;
    ldiff := nops(L)-ls ;
    for i from 1 to ldiff+1 do
        if L[i..i+ls-1] = s then
            return true;
        end if;
    end do:
    false;
end proc:
has40 := proc(n)
    option remember;
    subL(convert(n, base, 8), [0, 4]) ;
end proc:
isA044219 := proc(n)
    has40(n) and not has40(n-1) ;
end proc:
for n from 1 to 4000 do
    if isA044219(n) then printf("%d, ", n) ; end if;
end do: # R. J. Mathar, May 28 2016

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 8], {4, 0}]>0, 1, 0], {n, 2400}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 13 2018 *)

Crossrefs

Cf. A044600.

Sequence in context: A195088 A050429 A362841 * A044600 A189884 A175165

Adjacent sequences: A044216 A044217 A044218 * A044220 A044221 A044222

Keyword

nonn,base

Author

Clark Kimberling

Status

approved