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A105063 Define a(1)=0, a(2)=0, a(3)=8, a(4)=24 and then a(n)=66*a(n-2)+32-a(n-4). 2
0, 0, 8, 24, 560, 1616, 36984, 106664, 2440416, 7038240, 161030504, 464417208, 10625572880, 30644497520, 701126779608, 2022072419144, 46263741881280, 133426135166016, 3052705837384904, 8804102848537944, 201432321525522416 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Has the property that 17*a(n)^2+17*a(n)+1 is a square.

LINKS

Table of n, a(n) for n=1..21.

Index entries for linear recurrences with constant coefficients, signature (1,66,-66,-1,1).

FORMULA

a(n) = a(n-1) +66*a(n-2) -66*a(n-3) -a(n-4) +a(n-5). G.f.: 8*x^3*(1+x)^2/((1-x)*(x^2-8*x-1)*(x^2+8*x-1)). [R. J. Mathar, Nov 13 2009]

CROSSREFS

Cf. A103200, A001090.

Sequence in context: A002268 A050893 A037025 * A166483 A274303 A132586

Adjacent sequences:  A105060 A105061 A105062 * A105064 A105065 A105066

KEYWORD

nonn,easy

AUTHOR

Pierre CAMI, Apr 05 2005

EXTENSIONS

More terms from R. J. Mathar, Nov 13 2009

STATUS

approved

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Last modified May 15 06:18 EDT 2021. Contains 343909 sequences. (Running on oeis4.)