cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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

Original entry on oeis.org

1, -3, -7, -527, 164833, -98248054847, -3977703802948722503807, -510456831154766758152181998159655209453904127
Offset: 0

Views

Author

Gary W. Adamson, Jul 14 2006

Keywords

Comments

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

Examples

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

Crossrefs

Cf. A006495.

Programs

  • Maple
    a:= n-> Re((1 + 2*I)^(2^n));
    seq (a(n), n=0..10);
  • Mathematica
    Table[Re[(1 + 2I)^(2^n)], {n, 0, 8}] (* Stefan Steinerberger, Jul 23 2006 *)

Formula

a(n) = A006495(2^n).
a(n) = real part of (2 + sqrt(-1))^(2^n) for n >= 0.

Extensions

Corrected and extended by Stefan Steinerberger and Emeric Deutsch, Jul 23 2006