OFFSET
0,5
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,0,1,1).
FORMULA
EXAMPLE
G.f. = 1 + x + 2*x^4 + 3*x^5 + 3*x^6 + 5*x^7 + 10*x^8 + 16*x^9 + ...
MATHEMATICA
a[ n_] := Fibonacci[ Quotient[ n, 2] - 1] Fibonacci[ Quotient[ n, 2] + 1 + Mod[n, 2]];
LinearRecurrence[{1, 0, 1, 1}, {1, 1, 0, 0}, 50] (* Harvey P. Dale, Jan 19 2015 *)
CoefficientList[Series[(1 - x^2 - x^3) / (1 - x - x^3 - x^4), {x, 0, 70}], x] (* Vincenzo Librandi, Jan 20 2015 *)
PROG
(PARI) {a(n) = fibonacci( n\2 - 1 ) * fibonacci( n\2 + 1 + n%2 )};
(Magma) I:=[1, 1, 0, 0]; [n le 4 select I[n] else Self(n-1)+Self(n-3)+Self(n-4): n in [1..50]]; // Vincenzo Librandi, Jan 20 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Michael Somos, Jan 19 2014
STATUS
approved