A037807 Number of i such that d(i) < d(i-1), where Sum_{i=0..m} d(i)*9^i is the base-9 representation of n.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0

Offset

1,1

Links

Table of n, a(n) for n=1..90.

Maple

A037807 := proc(n)
    a := 0 ;
    dgs := convert(n, base, 9);
    for i from 2 to nops(dgs) do
        if op(i, dgs)<op(i-1, dgs) then
            a := a+1 ;
        end if;
    end do:
    a ;
end proc: # R. J. Mathar, Oct 16 2015

Crossrefs

Cf. A037824.

Sequence in context: A277159 A011724 A377191 * A037817 A297039 A239705

Adjacent sequences: A037804 A037805 A037806 * A037808 A037809 A037810

Keyword

nonn,base

Author

Clark Kimberling

Extensions

Sign in name corrected by R. J. Mathar, Oct 16 2015

Status

approved