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A174400 Hankel transform of A174399. 2
1, 0, -1, -1, -1, -2, -1, 3, 7, 8, 25, 37, -47, -318, -559, -2023, -7039, 496, 90431, 314775, 1139599, 8007614, 13512079, -154788437, -1247862041, -5097732072, -56844671623, -290379801907, 1403230649825, 32188159859842 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

Essentially a (1,-1) Somos-4 sequence.

LINKS

Table of n, a(n) for n=0..29.

FORMULA

a(n)=(a(n-1)*a(n-3)-a(n-2)^2)/a(n-4), n>=6.

MATHEMATICA

nxt[{a_, b_, c_, d_}]:={b, c, d, (d*b-c^2)/a}; Join[{1, 0}, NestList[nxt, {-1, -1, -1, -2}, 30][[All, 1]]] (* Harvey P. Dale, Sep 07 2017 *)

CROSSREFS

Sequence in context: A201615 A033640 A112027 * A178079 A258987 A174254

Adjacent sequences:  A174397 A174398 A174399 * A174401 A174402 A174403

KEYWORD

easy,sign

AUTHOR

Paul Barry, Mar 18 2010

STATUS

approved

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Last modified November 19 04:01 EST 2017. Contains 294912 sequences.