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URL: https://oeis.org/A057428

⇱ A057428 - OEIS

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A057428
Sign(-n): a(n) = 1 if -n > 0, = -1 if -n < 0, = 0 if n = 0.
5
0, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
OFFSET
0,1
FORMULA
G.f.: A(x) = -x/(1-x).
a(n) = -A057427(n).
Series reversion of g.f. A(x) is A(A(x)). - Nikolaos Pantelidis, Apr 13 2022
E.g.f.: 1 - exp(x). - Elmo R. Oliveira, Sep 22 2025
MATHEMATICA
Table[Sign[-n], {n, 0, 80}] (* Arkadiusz Wesolowski, Sep 16 2012 *)
PROG
(PARI) a(n) = sign(-n); \\ Michel Marcus, Apr 13 2022
CROSSREFS
First differences of A001489.
Cf. A057427.
Sequence in context: A165471 A165481 A165573 * A165574 A165581 A165586
KEYWORD
easy,sign
AUTHOR
Henry Bottomley, Sep 05 2000
STATUS
approved