OFFSET
0,2
COMMENTS
a(n)/a(n-1) tends to -8.
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-1, 56).
FORMULA
G.f.: (1+9*x)/(1+x-56*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*7^k.
a(n) = (16*7^n-(-8)^n)/15. - Klaus Brockhaus, Sep 26 2009
E.g.f.: (16*exp(7*x) - exp(-8*x))/15. - G. C. Greubel, Oct 21 2018
EXAMPLE
a(20)=8250317076996336, a(21)=1210673724145821328, a(22)=-748655967834026512, a(23)=68546384520000020880, a(24)=-110471118718705505552,...
MATHEMATICA
LinearRecurrence[{-1, 56}, {1, 8}, 50] (* G. C. Greubel, Oct 21 2018 *)
CoefficientList[Series[-(1+9x)/(56x^2-x-1), {x, 0, 20}], x] (* Harvey P. Dale, Dec 20 2023 *)
PROG
(PARI) vector(50, n, n--; (16*7^n-(-8)^n)/15) \\ G. C. Greubel, Oct 21 2018
(Magma) [(16*7^n-(-8)^n)/15: n in [0..50]]; // G. C. Greubel, Oct 21 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Philippe Deléham, Sep 21 2009
STATUS
approved