A057428 Sign(-n): a(n) = 1 if -n > 0, = -1 if -n < 0, = 0 if n = 0.

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

Author

Henry Bottomley, Sep 05 2000

Keywords

• easy
• sign

Links

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

Crossrefs

First differences of A001489.

Cf. A057427.

Programs

Mathematica

Table[Sign[-n], {n, 0, 80}] (* Arkadiusz Wesolowski, Sep 16 2012 *)

PARI

a(n) = sign(-n); \\ Michel Marcus, Apr 13 2022

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