OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Yu Tsumura, Primality tests for Fermat numbers and 2^(2k+1) +/- 2^(k+1)+1, arXiv:0912.2116 [math.NT], Dec 10 2009.
Index entries for linear recurrences with constant coefficients, signature (1,6,-6,-8,8).
FORMULA
G.f.: (1 + 4*x - 6*x^2 - 16*x^3 + 20*x^4)/((1-x)*(1-2*x)*(1+2*x)*(1-2*x^2)). - Colin Barker, Apr 27 2013
MATHEMATICA
Flatten[Table[2^(2*n+1) + 1 + 2^(n+1) {-1, 1}, {n, 0, 40}]] (* J. Mulder (jasper.mulder(AT)planet.nl), Jan 28 2010 *)
PROG
(PARI) my(x='x+O('x^40)); Vec((1+4*x-6*x^2-16*x^3+20*x^4)/((1-x)*(1- 2*x^2)*(1-4*x^2))) \\ G. C. Greubel, Jun 01 2019
(Magma) R<x>:=PowerSeriesRing(Integers(), 40); Coefficients(R!( (1+4*x-6*x^2-16*x^3+20*x^4)/((1-x)*(1- 2*x^2)*(1-4*x^2)) )); // G. C. Greubel, Jun 01 2019
(Sage) ((1+4*x-6*x^2-16*x^3+20*x^4)/((1-x)*(1- 2*x^2)*(1-4*x^2))).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Jun 01 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Dec 14 2009
EXTENSIONS
More terms from R. J. Mathar and J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010
New name from Joerg Arndt, Jun 03 2019
STATUS
approved