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A094361
Pair-reversal of 1,4,4,16,16...
0
4, 1, 16, 4, 64, 16, 256, 64, 1024, 256, 4096, 1024, 16384, 4096, 65536, 16384, 262144, 65536, 1048576, 262144, 4194304, 1048576, 16777216, 4194304, 67108864, 16777216, 268435456, 67108864, 1073741824, 268435456, 4294967296, 1073741824
OFFSET
0,1
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
Cf. A076736.
Sequence in context: A175844 A351434 A167343 * A187926 A285281 A285267
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Apr 26 2004
STATUS
approved