OFFSET
0,4
COMMENTS
Reverses elements a(2n+1) and a(2n+2) in A001045.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (-1,4,4).
FORMULA
G.f.: x*(1 + 2*x + 2*x^2)/((1+x)(1+2x)(1-2x)).
a(n) = (5*2^n - 6*0^n + 4(-1)^n - 3(-2)^n)/12. - Paul Barry, May 19 2003
a(n) - 2*a(n-1) is a signed version of A000225. - Paul Curtz, Mar 06 2008
MATHEMATICA
LinearRecurrence[{-1, 4, 4}, {0, 1, 1, 5}, 40] (* Harvey P. Dale, Nov 26 2022 *)
PROG
(Magma) [(5*2^n-6*0^n+4*(-1)^n-3*(-2)^n)/12: n in [0..40]]; // Vincenzo Librandi, Aug 13 2011
(PARI) a(n)=if(n, (5*2^n+4*(-1)^n-3*(-2)^n)/12, 0) \\ Charles R Greathouse IV, Oct 24 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, May 19 2003
STATUS
approved