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A069874
a(1) = a(2) = 1; a(n) = 2^a(n-1) + 2^a(n-2) for n > 2.
0
1, 1, 4, 18, 262160
OFFSET
1,3
MATHEMATICA
a[n_] := 1 /; n == 1 a[n_] := 1 /; n == 2 a[n_] := 2^a[n - 1] + 2^a[n - 2] /; n > 2; Table[a[i], {i, 1, 6}]
CROSSREFS
Sequence in context: A367533 A156491 A287677 * A222323 A012496 A024572
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Apr 23 2002
EXTENSIONS
a(6) has 78919 digits.
STATUS
approved