A091104 - OEIS

A091104

Expansion of (1-4x+24x^2)/((1-4x)(1+4x)).

1, -4, 40, -64, 640, -1024, 10240, -16384, 163840, -262144, 2621440, -4194304, 41943040, -67108864, 671088640, -1073741824, 10737418240, -17179869184, 171798691840, -274877906944, 2748779069440, -4398046511104, 43980465111040, -70368744177664

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OFFSET

0,2

COMMENTS

a(0)=1, a(2n-1)=-k^(2n-1), a(2n)=(3k-2)k^(2n-1), k=4; G.f.: (1-kx+2(k-1)kx^2)/((1-kx)(1+kx)), k=4.

LINKS

Table of n, a(n) for n=0..23.

Index entries for linear recurrences with constant coefficients, signature (0,16)

FORMULA

a(n)=3*4^n/4+7(-4)^n/4-6*0^n/4

CROSSREFS

Sequence in context: A169967 A061473 A367926 * A069539 A063997 A355841

Adjacent sequences: A091101 A091102 A091103 * A091105 A091106 A091107

KEYWORD

easy,sign

AUTHOR

Paul Barry, Dec 22 2003

STATUS

approved