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Search: id:A140721
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A140721 Alternated reading of A000302 and negated A002042. +0
1
1, -7, 4, -28, 16, -112, 64, -448, 256, -1792, 1024, -7168, 4096, -28672, 16384, -114688, 65536, -458752, 262144, -1835008, 1048576, -7340032, 4194304, -29360128, 16777216, -117440512, 67108864, -469762048, 268435456, -1879048192, 1073741824 (list; graph; listen)
OFFSET

0,2

COMMENT

Sequence can also be obtained by negating the first differences of A135520: a(n)=A135520(n)-A135520(n+1).

FORMULA

a(2n) = A000302(n). a(2n+1) = -A002042(n) .

a(2n) = -7a(2n-1). a(2n)-a(2n-1) = A002089(n-1). a(n)+a(n+1) = -3*A135520(n).

O.g.f.: (7x-1)/((2x-1)(2x+1)). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 14 2008

CROSSREFS

Sequence in context: A075536 A085047 A070427 this_sequence A038270 A100976 A152627

Adjacent sequences: A140718 A140719 A140720 this_sequence A140722 A140723 A140724

KEYWORD

sign,less

AUTHOR

Paul Curtz (bpcrtz(AT)free.fr), Jul 12 2008

EXTENSIONS

Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 14 2008

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Last modified December 10 00:48 EST 2009. Contains 170565 sequences.


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