A069874 a(1) = a(2) = 1; a(n) = 2^a(n-1) + 2^a(n-2) for n > 2.

1, 1, 4, 18, 262160

Offset

1,3

Links

Table of n, a(n) for n=1..5.

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

Adjacent sequences: A069871 A069872 A069873 * A069875 A069876 A069877

Keyword

nonn

Author

Joseph L. Pe, Apr 23 2002

Extensions

a(6) has 78919 digits.

Status

approved