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A198915
a(n) = 1 - 2^k + 4^k where k = 3^n.
1
3, 57, 261633, 18014398375264257, 5846006549323611672814736913013492849365380759553
OFFSET
0,1
LINKS
MAPLE
A198915:=n->4^(3^n) - 2^(3^n) + 1: seq(A198915(n), n=0..6); # Wesley Ivan Hurt, May 03 2017
MATHEMATICA
Table[4^(3^n) - 2^(3^n) + 1, {n, 0, 5}]
PROG
(PARI) a(n)=1<<(2*3^n)-1<<3^n+1 \\ Charles R Greathouse IV, Oct 31 2011
(Magma) [4^(3^n) - 2^(3^n) + 1: n in [0..7]]; // Vincenzo Librandi, Jun 29 2014
CROSSREFS
Cf. A051154.
Sequence in context: A127263 A134723 A133060 * A037107 A335293 A041735
KEYWORD
nonn,easy
AUTHOR
Artur Jasinski, Oct 31 2011
STATUS
approved