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A191871 a(n) = Numerator(n^2 / 2^n). 3
0, 1, 1, 9, 1, 25, 9, 49, 1, 81, 25, 121, 9, 169, 49, 225, 1, 289, 81, 361, 25, 441, 121, 529, 9, 625, 169, 729, 49, 841, 225, 961, 1, 1089, 289, 1225, 81, 1369, 361, 1521, 25, 1681, 441, 1849, 121, 2025, 529, 2209, 9, 2401, 625, 2601, 169, 2809, 729, 3025 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Interesting Plot: ListPlot[Table[f[n], {n, 0, 10000, 2}]]

a(n+1) = largest odd divisor of A000290(n+1). - Jeremy Gardiner, Aug 25 2013

In binary, remove all trailing zeros, then square. - Ralf Stephan, Aug 26 2013

A fractal sequence. The odd-numbered elements give the odd squares A016754. If these elements are removed, the original sequence is recovered. - Jeremy Gardiner, Sep 14 2013

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..5000

Index entries for sequences related to binary expansion of n

FORMULA

a(n) = A000265(n^2) = A000265(n)^2. - M. F. Hasler, Jun 19 2011

Recurrence: a(2n) = a(n), a(2n+1) = (2n+1)^2. - Ralf Stephan, Aug 26 2013

MATHEMATICA

f[n_] := Numerator[n^2/2^n]; Table[f[n], {n, 0, 200, 2}]

PROG

(PARI) a(n)=(n>>valuation(n, 2))^2 \\ Charles R Greathouse IV & M. F. Hasler, Jun 19 2011

CROSSREFS

Sequence in context: A013616 A205381 A237587 * A181318 A202006 A195278

Adjacent sequences:  A191868 A191869 A191870 * A191872 A191873 A191874

KEYWORD

nonn,frac,easy,less

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 18 2011

STATUS

approved

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Last modified December 8 16:27 EST 2016. Contains 278946 sequences.