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A105845 Numbers n such that n^2 = 41*m^2 + 41*m + 1. 1
1, 4511, 8609, 18486079, 35279681, 75755947231, 144576124129, 310447853266559, 592472921400961, 1272215226930411551, 2427953887325014049, 5213537689512973269439, 9949754437784986171841, 21365076179408937527749471, 40774091258088986007190369 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..15.

Index entries for linear recurrences with constant coefficients, signature (0,4098,0,-1).

FORMULA

Define a(1)=1, a(2)=4511, a(3)=4098*a(1)+a(2), a(4)=4098*a(2)+a(1), then a(n)=4098*a(n-2)-a(n-4).

G.f.: x*(x+1)*(x^2+4510*x+1) / ((x^2-64*x-1)*(x^2+64*x-1)). [Colin Barker, Mar 06 2013]

CROSSREFS

Cf. A105846 (associated m).

Sequence in context: A252628 A252623 A023684 * A107543 A234425 A209955

Adjacent sequences:  A105842 A105843 A105844 * A105846 A105847 A105848

KEYWORD

nonn,easy

AUTHOR

Pierre CAMI, Apr 22 2005

EXTENSIONS

a(10)-a(15) from Colin Barker, Mar 06 2013

STATUS

approved

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Last modified November 16 17:39 EST 2018. Contains 317275 sequences. (Running on oeis4.)