OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (208, -2718, 208, -1).
FORMULA
s(n) = [(a+1)/4)]*sqrt[(3a+1)(a-1)] where a=A103974(n)
a(n) = (((2 + Sqrt(3))^(2*n) - (2 - Sqrt(3))^(2*n))*(4 + (2 - Sqrt(3))^(2*n) + (2 + Sqrt(3))^(2*n)))/(12*Sqrt(3)) [From Terentyev Oleg, Nov 15 2009]
G.f. 12*x^2*(x^2-54*x+1) / ((x^2-194*x+1)*(x^2-14*x+1)). - Colin Barker, Apr 10 2013
MATHEMATICA
Block[{a, nmax = 25}, a[n_] := ((-(2 - Sqrt[3])^(2 n) + (2 + Sqrt[3])^( 2 n)) (4 + (2 - Sqrt[3])^(2 n) + (2 + Sqrt[3])^(2 n)))/( 12 Sqrt[3]); Expand[a /@ Range[0, nmax]]] [From Terentyev Oleg, Nov 15 2009]
LinearRecurrence[{208, -2718, 208, -1}, {0, 12, 1848, 351780}, 20] (* Harvey P. Dale, Mar 02 2018 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Feb 24 2005
EXTENSIONS
More terms from Rick L. Shepherd, Sep 05 2005
More terms from Colin Barker, Apr 10 2013
STATUS
approved