OFFSET
0,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
FORMULA
E.g.f.: sqrt((1+2*x)/(1+4*x)).
D-finite with recurrence: a(n) +(6*n-5)*a(n-1) +8*(n-1)*(n-2)*a(n-2)=0. - R. J. Mathar, Jan 24 2020
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Sqrt[(1+2x)/(1+4x)], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Apr 23 2014 *)
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Mar 26 2007
STATUS
approved