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A090591 G.f.: 1/(1 - 2x + 8x^2). 4
1, 2, -4, -24, -16, 160, 448, -384, -4352, -5632, 23552, 92160, -4096, -745472, -1458176, 3047424, 17760256, 11141120, -119799808, -328728576, 300941312, 3231711232, 4055891968, -17741905920, -67930947584 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

(1,2) entry of powers of the orthogonal design shown below:

+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

Pisano period lengths: 1, 1, 8, 1, 24, 8, 7, 1, 24, 24, 10, 8, 56, 7, 24, 1, 144, 24, 120, 24, ... - R. J. Mathar, Aug 10 2012

LINKS

Table of n, a(n) for n=1..25.

Index entries for linear recurrences with constant coefficients, signature (2,-8)

FORMULA

Binomial transform of (1+x)/(1+7x^2).

a(0)=1, a(1)=2, a(n) = 2*a(n-1) - 8*a(n-2) for n>1. - Philippe Deléham, Sep 19 2009

MATHEMATICA

Join[{a=1, b=2}, Table[c=2*b-8*a; a=b; b=c, {n, 60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 18 2011 *)

PROG

(Sage) [lucas_number1(n, 2, 8) for n in xrange(1, 21)] # Zerinvary Lajos, Apr 23 2009

CROSSREFS

Cf. A087621, A090590.

Sequence in context: A269573 A147761 A214299 * A098656 A138611 A171459

Adjacent sequences:  A090588 A090589 A090590 * A090592 A090593 A090594

KEYWORD

sign

AUTHOR

Simone Severini, Dec 04 2003

EXTENSIONS

Formulae from Paul Barry, Dec 05 2003

Corrected by T. D. Noe, Dec 11 2006

STATUS

approved

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Last modified March 29 18:39 EDT 2017. Contains 284273 sequences.