OFFSET
1,2
COMMENTS
LINKS
FORMULA
a(n) = 5^((1/4)*(2*n-1+(-1)^n)).
G.f.: x*(1+5*x)/(1-5*x^2).
MATHEMATICA
LinearRecurrence[{0, 5}, {1, 5}, 30] (* Harvey P. Dale, Mar 18 2023 *)
PROG
(Magma) [ n le 2 select 4*n-3 else 5*Self(n-2): n in [1..30] ];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, Jul 19 2009
STATUS
approved