login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A139689 If (n-th Chen prime) + 2 is a prime then 1 else 0. 3
0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = A010051(A139690(n)) = 1 - A064911(A139690(n)).

LINKS

R. Zumkeller, Table of n, a(n) for n = 1..1000

Index entries for characteristic functions

Eric Weisstein's World of Mathematics, Chen Prime

FORMULA

a(n) = 2 - A001222(A139690(n)).

CROSSREFS

Sequence in context: A327861 A131929 A100821 * A204175 A285255 A324823

Adjacent sequences:  A139686 A139687 A139688 * A139690 A139691 A139692

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Apr 29 2008

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 20 14:54 EST 2019. Contains 329337 sequences. (Running on oeis4.)