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A042693
Denominators of continued fraction convergents to sqrt(876).
2
1, 1, 2, 5, 72, 149, 221, 370, 21681, 22051, 43732, 109515, 1576942, 3263399, 4840341, 8103740, 474857261, 482961001, 957818262, 2398597525, 34538183612, 71474964749, 106013148361, 177488113110, 10400323708741, 10577811821851, 20978135530592, 52534082883035
OFFSET
0,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,21902,0,0,0,0,0,0,0,-1).
FORMULA
G.f.: -(x^14 -x^13 +2*x^12 -5*x^11 +72*x^10 -149*x^9 +221*x^8 -370*x^7 -221*x^6 -149*x^5 -72*x^4 -5*x^3 -2*x^2 -x -1) / ((x^8 -148*x^4 +1)*(x^8 +148*x^4 +1)). - Colin Barker, Dec 21 2013
a(n) = 21902*a(n-8) - a(n-16) for n>15. - Vincenzo Librandi, Dec 21 2013
MATHEMATICA
Denominator[Convergents[Sqrt[876], 30]] (* Vincenzo Librandi Dec 21 2013 *)
PROG
(Magma) I:=[1, 1, 2, 5, 72, 149, 221, 370, 21681, 22051, 43732, 109515, 1576942, 3263399, 4840341, 8103740]; [n le 16 select I[n] else 21902*Self(n-8)-Self(n-16): n in [1..70]]; // Vincenzo Librandi, Dec 21 2013
CROSSREFS
Sequence in context: A290864 A309366 A007506 * A328746 A172037 A301993
KEYWORD
nonn,frac,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Dec 21 2013
STATUS
approved