A037802 Number of i such that d(i) < d(i-1), where Sum_{i=0..m} d(i)*4^i is the base-4 representation of n.

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

Offset

1,27

Links

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

Maple

A037802 := proc(n)
    a := 0 ;
    dgs := convert(n, base, 4);
    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

A037802[n_] := Count[Differences[IntegerDigits[n, 4]], _?Positive];
Array[A037802, 100] (* Paolo Xausa, Jan 26 2026 *)

Prog

(MATLAB) n = 1:10000; a = arrayfun(@(m) sum(diff(dec2base(m, 4)-'0')>0), n); % Chris R. Rehmann, Nov 24 2025

Crossrefs

Cf. A007090, A037819.

Cf. A037800, A037801, A037803, A037804, A037805, A037806, A037807, A037808.

Sequence in context: A340607 A319659 A050372 * A037879 A178535 A025449

Adjacent sequences: A037799 A037800 A037801 * A037803 A037804 A037805

Keyword

nonn,base,easy

Author

Clark Kimberling

Extensions

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

Status

approved