A044819 Positive integers having distinct base-8 run lengths.

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, 255, 256

Offset

1,2

Links

David A. Corneth, Table of n, a(n) for n = 1..10000

Example

222 = 336_8 has a run length of two and a run length of 1, which are distinct lengths, so 222 is in the sequence. - R. J. Mathar, Jan 18 2018

Maple

rlset := proc(L::list)
    local lset, rl, i ;
    lset := [] ;
    rl := 1 ;
    for i from 2 to nops(L) do
        if op(i, L) = op(i-1, L) then
            rl := rl+1 ;
        else
            lset := [op(lset), rl] ;
            rl := 1;
        end if;
    end do:
    lset := [op(lset), rl] ;
end proc:
isA044819 := proc(n)
    local dgs, rl;
    dgs := convert(n, base, 8) ;
    rl := rlset(dgs) ;
    if nops(rl) = nops( convert(rl, set)) then
        true;
    else
        false;
    end if;
end proc:
for n from 1 to 400 do
    if isA044819(n) then
        printf("%d, ", n) ;
    end if;
end do: # R. J. Mathar, Jan 18 2018

Crossrefs

Cf. A044813, A044814, A044815, A044816, A044817, A044818, A044819, A044820, A044821, A044822, A044823, A044824, A044825, A044826, A044827 (base 2 to base 16).

Sequence in context: A083376 A044957 A297142 * A048305 A043711 A296706

Adjacent sequences: A044816 A044817 A044818 * A044820 A044821 A044822

Keyword

nonn,base

Author

Clark Kimberling

Status

approved