A037810 Number of i such that d(i) <= d(i-1), where Sum_{i=0..m} d(i)*3^i is the base-3 representation of n.

0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 0, 1, 1, 1, 1, 2, 2, 2, 2, 1, 2, 2, 1, 1, 2, 2, 2, 2, 2, 3, 3, 2, 2, 3, 2, 2, 2, 1, 2, 2, 2, 2, 3, 2, 2, 2, 1, 2, 2, 1, 1, 2, 1, 1, 1, 1, 2, 2, 1, 1, 2, 2, 2, 2, 1, 2, 2, 2, 2, 3, 3, 3, 3, 2, 3, 3, 2, 2, 3, 2

Offset

1,13

Comments

Equivalently, number of nonnegative terms in the first differences of the digits of the ternary representation of n. - Paolo Xausa, Nov 19 2025

Links

Chris R. Rehmann, Table of n, a(n) for n = 1..10000

Maple

A037810 := proc(n)
    a := 0 ;
    dgs := convert(n, base, 3);
    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

Mathematica

A037810[n_] := Count[Differences[IntegerDigits[n, 3]], _?NonNegative];
Array[A037810, 100] (* Paolo Xausa, Nov 19 2025 *)

Prog

(MATLAB) n = 1:10000; a = arrayfun(@(m) sum(diff(dec2base(m, 3)-'0')>=0), n); % Chris R. Rehmann, Nov 17 2025

Crossrefs

Cf. A007089, A037826.

Cf. A037809, A037811, A037812, A037813, A037814, A037815, A037816, A037817.

Sequence in context: A362423 A274274 A072550 * A335211 A038769 A327818

Adjacent sequences: A037807 A037808 A037809 * A037811 A037812 A037813

Keyword

nonn,base,easy

Author

Clark Kimberling

Extensions

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

Status

approved