cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A140721 Alternated reading of A000302 and negated A002042.

Original entry on oeis.org

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
Offset: 0

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Author

Paul Curtz, Jul 12 2008

Keywords

Comments

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, Jul 14 2008

Extensions

Edited by R. J. Mathar, Jul 14 2008