OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (23,-172,420).
FORMULA
a(n) = 9*6^n -49*7^n/3 +25*10^n/3. - R. J. Mathar, Jun 30 2013
a(0)=1, a(1)=23, a(2)=357; for n>2, a(n) = 23*a(n-1) -172*a(n-2) +420*a(n-3). - Vincenzo Librandi, Jul 04 2013
a(n) = 17*a(n-1) -70*a(n-2) +6^n. - Vincenzo Librandi, Jul 04 2013
MATHEMATICA
CoefficientList[Series[1 / ((1 - 6 x) (1 - 7 x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jul 04 2013 *)
LinearRecurrence[{23, -172, 420}, {1, 23, 357}, 20] (* Harvey P. Dale, Sep 24 2016 *)
PROG
(Magma) m:=20; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/((1-6*x)*(1-7*x)*(1-10*x)))); /* or */ I:=[1, 23, 357]; [n le 3 select I[n] else 23*Self(n-1)-172*Self(n-2)+420*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Jul 04 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved