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A001054 a(n) = a(n-1)*a(n-2) - 1. 1
0, 1, -1, -2, 1, -3, -4, 11, -45, -496, 22319, -11070225, -247076351776, 2735190806339469599, -675800965841611881515781657825, -1848444588685310753420392017318175868503407962176 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

LINKS

John Cerkan, Table of n, a(n) for n = 0..21

MAPLE

a:= proc (n) option remember;

if n<2 then n

else a(n-1)*a(n-2) - 1

end if

end proc;

seq(a(n), n = 0..15); # G. C. Greubel, Sep 20 2019

MATHEMATICA

RecurrenceTable[{a[0]==0, a[1]==1, a[n]==a[n-1]*a[n-2] -1}, a, {n, 0, 15}] (* G. C. Greubel, Sep 20 2019 *)

PROG

(PARI) m=15; v=concat([0, 1], vector(m-2)); for(n=3, m, v[n]=v[n-1]*v[n-2] -1 ); v \\ G. C. Greubel, Sep 20 2019

(MAGMA) I:=[0, 1]; [n le 2 select I[n] else Self(n-1)*Self(n-2) -1: n in [1..15]]; // G. C. Greubel, Sep 20 2019

(Sage)

def a(n):

    if (n<2): return n

    else: return a(n-1)*a(n-2) -1

[a(n) for n in (0..15)] # G. C. Greubel, Sep 20 2019

(GAP) a:=[0, 1];; for n in [3..15] do a[n]:=a[n-1]*a[n-2] -1; od; a; # G. C. Greubel, Sep 20 2019

CROSSREFS

Sequence in context: A166476 A052950 A086851 * A218209 A141487 A217103

Adjacent sequences:  A001051 A001052 A001053 * A001055 A001056 A001057

KEYWORD

easy,sign

AUTHOR

R. K. Guy

STATUS

approved

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Last modified August 8 05:50 EDT 2020. Contains 336290 sequences. (Running on oeis4.)