OFFSET
0,2
COMMENTS
The initial terms coincide with those of A003949, although the two sequences are eventually different.
First disagreement at index 17: a(17) = 19747769352171, A003949(17) = 19747769352192. - Klaus Brockhaus, Mar 30 2011
Computed with MAGMA using commands similar to those used to compute A154638.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..500
Index entries for linear recurrences with constant coefficients, signature (5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,-15).
FORMULA
G.f.: (t^17 + 2*t^16 + 2*t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 + 2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/ (15*t^17 - 5*t^16 - 5*t^15 - 5*t^14 - 5*t^13 - 5*t^12 - 5*t^11 - 5*t^10 - 5*t^9 - 5*t^8 - 5*t^7 - 5*t^6 - 5*t^5 - 5*t^4 - 5*t^3 - 5*t^2 - 5*t + 1).
G.f.: (1+t)*(1-t^17)/(1 - 6*t + 20*t^17 - 15*t^18). - G. C. Greubel, Mar 24 2021
MATHEMATICA
CoefficientList[Series[(1+t)*(1-t^17)/(1 -6*t +20*t^17 -15*t^18), {t, 0, 50}], t] (* G. C. Greubel, Aug 03 2016; Mar 24 2021 *)
coxG[{17, 15, -5, 40}] (* The coxG program is at A169452 *) (* G. C. Greubel, Mar 24 2021 *)
PROG
(Magma)
R<t>:=PowerSeriesRing(Integers(), 40);
Coefficients(R!( (1+t)*(1-t^17)/(1 -6*t +20*t^17 -15*t^18) )); // G. C. Greubel, Mar 24 2021
(Sage)
def A168684_list(prec):
P.<t> = PowerSeriesRing(ZZ, prec)
return P( (1+t)*(1-t^17)/(1 -6*t +20*t^17 -15*t^18) ).list()
A168684_list(40) # G. C. Greubel, Mar 24 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
John Cannon and N. J. A. Sloane, Dec 03 2009
STATUS
approved