A145645 - OEIS

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A145645

Numbers n such that (binary weight of n)/(length of binary representation of n) equals 1/3.

4, 33, 34, 36, 40, 48, 259, 261, 262, 265, 266, 268, 273, 274, 276, 280, 289, 290, 292, 296, 304, 321, 322, 324, 328, 336, 352, 385, 386, 388, 392, 400, 416, 448, 2055, 2059, 2061, 2062, 2067, 2069, 2070, 2073, 2074, 2076, 2083, 2085, 2086, 2089, 2090, 2092

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OFFSET

1,1

COMMENTS

Generalization: numbers such that A000120(n)/A070939(n)=c. For c = 1 we have A000225, for c = 1/2 we have A031443. We may take c=p/q, 1 <= p < q. All sequences of this type show the same kind of "flocking" behavior.

LINKS

Table of n, a(n) for n=1..50.

MAPLE

q:= n-> (l-> nops(l)=3*add(i, i=l))(Bits[Split](n)):

select(q, [$1..2200])[]; # Alois P. Heinz, Feb 04 2022

CROSSREFS

Cf. A000120, A070939, A000523, A000225, A031443.

Sequence in context: A372923 A347484 A059904 * A042831 A092207 A133630

Adjacent sequences: A145642 A145643 A145644 * A145646 A145647 A145648

KEYWORD

base,easy,nonn

AUTHOR

Ctibor O. Zizka, Oct 15 2008

STATUS

approved