OFFSET
1,1
REFERENCES
K. S. Bhanu (bhanu_105(AT)yahoo.com) and M. N. Deshpande, An interesting sequence of quadruples and related open problems, Institute of Sciences, Nagpur, India, Preprint, 2005.
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,8,0,-1).
FORMULA
G.f.: x*(11 + 19*x + x^2 - x^3)/(1 - 8*x^2 + x^4). - Georg Fischer, May 24 2019
MAPLE
b[1]:=11:b[2]:=19:b[3]:=89:b[4]:=151: for n from 5 to 28 do b[n]:=sqrt(b[n-4]^2+60*b[n-2]^2+4*b[n-2]*sqrt(210+15*b[n-4]^2)) od:seq(b[n], n=1..28); # Emeric Deutsch, Apr 13 2005
MATHEMATICA
LinearRecurrence[{0, 8, 0, -1}, {11, 19, 89, 151}, 30] (* Georg Fischer, May 24 2019 *)
PROG
(PARI) my(x='x+O('x^30)); Vec(x*(11+19*x+x^2-x^3)/(1-8*x^2+x^4)) \\ G. C. Greubel, May 24 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 30); Coefficients(R!( x*(11+19*x+x^2-x^3)/(1-8*x^2+x^4) )); // G. C. Greubel, May 24 2019
(Sage) a=(x*(11+19*x+x^2-x^3)/(1-8*x^2+x^4)).series(x, 30).coefficients(x, sparse=False); a[1:] # G. C. Greubel, May 24 2019
(GAP) a:=[11, 19, 89, 151];; for n in [5..30] do a[n]:=8*a[n-2]-a[n-4]; od; a; # G. C. Greubel, May 24 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
K. S. Bhanu and M. N. Deshpande, Mar 24 2005
EXTENSIONS
More terms from Pierre CAMI and Emeric Deutsch, Apr 13 2005
STATUS
approved