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A073019 Numbers n such that the absolute value of the real part of (1+2*I)^n is prime. 0
2, 3, 4, 5, 7, 11, 13, 17, 19, 89, 163, 167, 233, 251, 349, 401, 757, 1423, 3049, 3643, 11987 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..21.

FORMULA

{n: |A006495(n)| in A000040}.

MAPLE

A006495 := proc(n) add((-4)^l*binomial(n, 2*l), l=0..floor(n/2)) ; end proc:

isA073019 := proc(n) isprime(abs(A006495(n))) ; end proc:

for n from 1 do if isA073019(n) then print(n) ; end if; end do: # R. J. Mathar, Sep 06 2011

MATHEMATICA

x=1; For[n=1, n<=14000, n++, {x=(1+2*I)*x, If[PrimeQ[Re[x]], Print[n]]}]

CROSSREFS

Cf. A006495.

Sequence in context: A211781 A046022 A175787 * A174291 A007885 A192586

Adjacent sequences:  A073016 A073017 A073018 * A073020 A073021 A073022

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Aug 03 2002

EXTENSIONS

Edited by John W. Layman, Aug 13 2002

a(21) from Robert G. Wilson v, Aug 22 2002

STATUS

approved

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Last modified October 20 18:53 EDT 2014. Contains 248371 sequences.