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A140407 A000225 interleaved with A000051. 1
1, 2, 3, 3, 7, 5, 15, 9, 31, 17, 63, 33, 127, 65, 255, 129, 511, 257, 1023, 513, 2047, 1025, 4095, 2049, 8191, 4097, 16383, 8193, 32767, 16385, 65535, 32769, 131071, 65537, 262143, 131073, 524287, 262145, 1048575, 524289, 2097151, 1048577, 4194303 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (-1, 2, 2).

FORMULA

a(2n) = A000225(n+1) = A135530(2n)-1. a(2n+1)=A000051(n) = 1+A135530(2n+1).

a(n) = -a(n-1)+2a(n-2)+2a(n-3). a(2n)+a(2n+1) = 3*A000079(n).

O.g.f.: (1+3x+3x^2)/((1+x)(1-2x^2)). - R. J. Mathar, Jul 08 2008

MATHEMATICA

LinearRecurrence[{-1, 2, 2}, {1, 2, 3}, 50] (* Harvey P. Dale, Apr 03 2013 *)

CROSSREFS

Sequence in context: A256447 A076557 A228548 * A063670 A253357 A185909

Adjacent sequences:  A140404 A140405 A140406 * A140408 A140409 A140410

KEYWORD

nonn

AUTHOR

Paul Curtz, Jun 16 2008

EXTENSIONS

Edited and extended by R. J. Mathar, Jul 08 2008

STATUS

approved

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Last modified March 26 14:18 EDT 2019. Contains 321497 sequences. (Running on oeis4.)