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A269265
a(0) = a(1) = 1; thereafter a(n) = a(n-1) + a(n-2) if n is even, otherwise a(n) = a(n-1)^2.
0
1, 1, 2, 4, 6, 36, 42, 1764, 1806, 3261636, 3263442, 10650053687364, 10650056950806, 113423713055411194304049636, 113423713055421844361000442, 12864938683278671740537145884937248491231415124195364, 12864938683278671740537145998360961546653259485195806
OFFSET
0,3
COMMENTS
The first bisection is A007018, the second bisection is A174864 (with an only initial 1).
After 2, all terms belong to A238411.
FORMULA
a(n) = ( 1 + Sum_{k=0..floor(n/2)-1} a(2*k+1) )^(3-(-1)^n)/2 for n>1.
MATHEMATICA
a[n_] := If[OddQ@n, a[n - 1] + a[n - 2], a[n - 1]^2]; a[0] = 1; Array[a, 17]
PROG
(Magma) [n le 2 select 1 else IsEven(n) select Self(n-1)^2 else Self(n-1)+Self(n-2): n in [1..20]];
CROSSREFS
KEYWORD
nonn
AUTHOR
Vincenzo Librandi, Feb 23 2016
EXTENSIONS
Edited and extended by Bruno Berselli, Feb 25 2016
STATUS
approved