OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (25,-47,23).
FORMULA
From Harvey P. Dale, Feb 05 2012: (Start)
a(1)=1, a(2)=25, a(3)=578, a(n) = 25*a(n-1) - 47*a(n-2) + 23*a(n-3).
G.f.: -x/((-1+x)^2*(-1+23*x)). (End)
From Elmo R. Oliveira, Mar 30 2025: (Start)
E.g.f.: exp(x)*(23*exp(22*x) - 22*x - 23)/484.
a(n) = (23^(n+1) - 22*n - 23)/484. (End)
MATHEMATICA
Transpose[NestList[{First[#]+1, 23Last[#]+First[#]+1}&, {1, 1}, 20]][[2]] (* or *) LinearRecurrence[{25, -47, 23}, {1, 25, 578}, 20] (* Harvey P. Dale, Feb 05 2012 *)
PROG
(Magma) I:=[1, 25, 578]; [n le 3 select I[n] else 25*Self(n-1)-47*Self(n-2)+23*Self(n-3): n in [1..30]]; // Vincenzo Librandi, Feb 05 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved