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A120905 Real part of (1 + 2i)^(2^n) where i is sqrt(-1). 3

%I #13 Sep 16 2015 05:01:27

%S 1,-3,-7,-527,164833,-98248054847,-3977703802948722503807,

%T -510456831154766758152181998159655209453904127

%N Real part of (1 + 2i)^(2^n) where i is sqrt(-1).

%C The next term a(8) has 90 digits and is too large to be displayed here.

%F a(n) = A006495(2^n).

%F a(n) = real part of (2 + sqrt(-1))^(2^n) for n >= 0.

%e a(3) = -527 since (1 + 2i)^8 = (-527 + 336i) = A006495(8).

%p a:= n-> Re((1 + 2*I)^(2^n));

%p seq (a(n), n=0..10);

%t Table[Re[(1 + 2I)^(2^n)], {n, 0, 8}] (* _Stefan Steinerberger_, Jul 23 2006 *)

%Y Cf. A006495.

%K sign

%O 0,2

%A _Gary W. Adamson_, Jul 14 2006

%E Corrected and extended by _Stefan Steinerberger_ and _Emeric Deutsch_, Jul 23 2006

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Last modified March 28 22:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)