OFFSET
0,1
LINKS
FORMULA
a(n) = k^(n/2)(1+k*sqrt(k)-(1-ksqrt(k))(-1)^n)/(2*sqrt(k)), the pair reversal of 1,k,k,k^2,k^2,k^3,k^3,... for k=4.
G.f.: (4+x)/(1-4*x^2).
a(n) = (9*2^n+7*(-2)^n)/4.
Recurrence: a(n) = 4a(n-2), a(0)=4, a(1)=1. - Ralf Stephan, Jul 17 2013
MATHEMATICA
LinearRecurrence[{0, 4}, {4, 1}, 50] (* Harvey P. Dale, Apr 15 2017 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Apr 26 2004
STATUS
approved