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A112455 a(n) = -a(n-2)-a(n-3). +0
2
-3, 0, 2, 3, -2, -5, -1, 7, 6, -6, -13, 0, 19, 13, -19, -32, 6, 51, 26, -57, -77, 31, 134, 46, -165, -180, 119, 345, 61, -464, -406, 403, 870, 3, -1273, -873, 1270, 2146, -397, -3416, -1749, 3813, 5165, -2064, -8978, -3101, 11042, 12079, -7941 (list; graph; listen)
OFFSET

0,1

COMMENT

This sequence resembles the Perrin sequence, A001608. Like many such sequences with a(1)=0, any prime p divides a(p). The first pseudoprime (composite n divides a(n)) is 121.

FORMULA

a(n)= - trace({{0, 0, -1}, {1, 0, -1}, {0, 1, 0}})^n - Artur Jasinski (grafix(AT)csl.pl), Jan 10 2007

G.f.: -(3+x^2)/(1+x^2+x^3). a(n) = -3*A077962(n)-A077962(n-2). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 24 2009]

MAPLE

Table[ -Tr[MatrixPower[{{0, 0, -1}, {1, 0, -1}, {0, 1, 0}}, n]], {n, 1, 50}] - Artur Jasinski (grafix(AT)csl.pl), Jan 10 2007

CROSSREFS

Cf. A001608, A112458.

Sequence in context: A119493 A032531 A143394 this_sequence A001608 A159977 A112974

Adjacent sequences: A112452 A112453 A112454 this_sequence A112456 A112457 A112458

KEYWORD

sign

AUTHOR

Anthony C Robin (anthony_robin(AT)hotmail.com), Dec 13 2005

EXTENSIONS

Edited by Don Reble (djr(AT)nk.ca), Jan 25 2006

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Last modified December 7 23:50 EST 2009. Contains 170430 sequences.


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