A389826 - OEIS

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A389826

a(n) = floor(n*A030101(n)/(n + A030101(n))).

1

0, 0, 1, 0, 2, 2, 3, 0, 4, 3, 5, 2, 5, 4, 7, 0, 8, 6, 10, 4, 10, 8, 12, 2, 10, 7, 13, 5, 12, 10, 15, 0, 16, 11, 20, 7, 19, 15, 23, 4, 19, 14, 23, 10, 22, 17, 26, 2, 20, 13, 25, 9, 23, 18, 28, 6, 23, 16, 28, 12, 26, 20, 31, 0, 32, 22, 39, 13, 37, 28, 43, 8, 36

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,5

LINKS

Table of n, a(n) for n=1..73.

Ctibor O. Zizka, Scatter Plot n vs. a(n) for n = 1 to 17000

FORMULA

For k >= 1:

a(2^k - 1) = 2^(k - 1) - 1.

a(2^k) = 0.

a(2^k + 1) = 2^(k - 1).

MATHEMATICA

a[n_] := With[{r = IntegerReverse[n, 2]}, Floor[n*r/(n+r)]]; Array[a, 100] (* Amiram Eldar, Jan 12 2026 *)

CROSSREFS

Cf. A030101, A055944.

Sequence in context: A035173 A263254 A257989 * A095201 A272143 A095058

Adjacent sequences: A389823 A389824 A389825 * A389827 A389828 A389829

KEYWORD

nonn,base

AUTHOR

Ctibor O. Zizka, Jan 12 2026

STATUS

approved