login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A183059 Cyclops primes p such that 2p+1 is also a Cyclops prime. 1
12011, 12041, 13049, 18041, 21011, 22013, 28019, 29021, 29033, 31019, 33023, 37013, 37049, 38039, 42023, 43013, 48029, 1110269, 1120349, 1120481, 1130273, 1130429, 1140143, 1140311, 1140341, 1140383, 1140413, 1140449, 1160129, 1160213, 1160429, 1170173, 1170329, 1170443 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes p such that both p and 2p+1 are Cyclops primes A134809.

By definition all terms are also Sophie Germain primes A005384.

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

a(1) = 12011 is in the sequence because 12011 is a Cyclops prime A134809 and 2*12011+1 = 24023 is also a Cyclops prime.

MAPLE

isA134808 := proc(n) local dgs, ndgs; dgs := convert(n, base, 10) ; mdg := (nops(dgs)+1)/2 ; if type(nops(dgs), 'even') then false; elif n = 0 then true; else if op(mdg, dgs) <> 0 then false; else if mul(op(k, dgs), k=1..mdg-1) =0 or mul(op(k, dgs), k=mdg+1..nops(dgs)) = 0 then false; else true; end if; end if; end if; end proc:

isA134809 := proc(n) isprime(n) and isA134808(n) ; end proc:

isA183059 := proc(n) isA134809(n) and isA134809(2*n+1) ; end proc:

for n from 0 to 1200000 do if isA183059(n) then printf("%d, ", n); end if; end do: # R. J. Mathar, Jan 05 2011

CROSSREFS

Cf. A005384, A134808, A134809, A183058.

Sequence in context: A251163 A236607 A156713 * A287046 A235308 A064966

Adjacent sequences:  A183056 A183057 A183058 * A183060 A183061 A183062

KEYWORD

nonn,base,less

AUTHOR

Omar E. Pol, Dec 25 2010

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 26 14:05 EDT 2022. Contains 354884 sequences. (Running on oeis4.)