A037820 Number of i such that d(i) > d(i-1), where Sum_{i=0..m} d(i)*5^i is the base-5 representation of n.

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

Offset

1,55

Links

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

Maple

A037820 := proc(n)
    a := 0 ;
    dgs := convert(n, base, 5);
    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 15 2015

Mathematica

A037820[n_] := Count[Differences[IntegerDigits[n, 5]], _?Negative];
Array[A037820, 100] (* Paolo Xausa, Jan 26 2026 *)

Prog

(MATLAB) n = 1:10000; a = arrayfun(@(m) sum(diff(dec2base(m, 5)-'0')<0), n); % Chris R. Rehmann, Nov 18 2025

Crossrefs

Cf. A007091, A037803.

Cf. A033264, A037818, A037819, A037821, A037822, A037823, A037824, A037825.

Sequence in context: A349082 A281010 A316864 * A076493 A278907 A037910

Adjacent sequences: A037817 A037818 A037819 * A037821 A037822 A037823

Keyword

nonn,base,easy

Author

Clark Kimberling

Extensions

Sign in Name corrected by R. J. Mathar, Oct 15 2015

Status

approved