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A078159 a(n) = A055086(2^n). 3
2, 3, 4, 7, 10, 15, 21, 31, 44, 63, 89, 127, 180, 255, 361, 511, 723, 1023, 1447, 2047, 2895, 4095, 5791, 8191, 11584, 16383, 23169, 32767, 46339, 65535, 92680, 131071, 185362, 262143, 370726, 524287, 741454, 1048575, 1482909, 2097151, 2965819, 4194303, 5931640, 8388607 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(2n-2)=2^n-1 and a(n)=2a(n-2)+1 generally.

LINKS

Table of n, a(n) for n=1..44.

MATHEMATICA

Table[ Length[ Union[ Table[ Floor[2^w/j], {j, 1, 2^w}]]], {w, 1, 25}]

PROG

(PARI) a(n) = ceil(2*sqrt(2^n+1)) - 2; \\ Michel Marcus, Sep 02 2019

CROSSREFS

Cf. A055086, A078160, A078161 & A078162.

Sequence in context: A145467 A325341 A039841 * A129490 A018132 A329758

Adjacent sequences:  A078156 A078157 A078158 * A078160 A078161 A078162

KEYWORD

nonn

AUTHOR

Labos Elemer, Nov 27 2002

EXTENSIONS

Extended by Robert G. Wilson v, Dec 02 2002

More terms from Michel Marcus, Sep 02 2019

STATUS

approved

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Last modified March 31 13:07 EDT 2020. Contains 333151 sequences. (Running on oeis4.)