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!)
A174920 List of primes p1 such that (p1,p2) are twin primes where both 2*p1+p2 and p1+2*p2 are primes. 10
3, 5, 59, 269, 1949, 2999, 6359, 11489, 11549, 14549, 18539, 19889, 21839, 31079, 32909, 32969, 33329, 33599, 42569, 42839, 50459, 53549, 58109, 68879, 70199, 74609, 79229, 80909, 93809, 96329, 98909, 104309, 109139, 114599, 121019, 125789 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Terms >5 are congruent to 29 mod 30. - Zak Seidov, May 10 2012
Also 2*p1+p2 and p1+2*p2 are twin primes. - Zak Seidov, May 10 2012
LINKS
FORMULA
From Wesley Ivan Hurt, May 03 2022: (Start)
a(n) = A132929(n) - 1.
a(n) = A177336(n) - 2. (End)
EXAMPLE
a(1)=3 because 3, 5 are twin primes and 2*3+5=11, 3+2*5=13 are also primes.
MAPLE
select(q -> isprime(q) and isprime(q+2) and isprime(3*q+2) and isprime(3*q+4), [3, 5, seq(i, i=29..200000, 30)]); # Robert Israel, May 06 2019
MATHEMATICA
lst={}; Do[p1=Prime[n]; p2=p1+2; If[PrimeQ[p2]&&PrimeQ[2*p1+p2]&&PrimeQ[p1+2*p2], AppendTo[lst, p1]], {n, 8!}]; lst
PROG
(Magma) [NthPrime(n): n in [1..12000] | forall{p: p in [NthPrime(n)+2, 3*NthPrime(n)+2, 3*NthPrime(n)+4] | IsPrime(p)}]; // Bruno Berselli, May 10 2012
CROSSREFS
Sequence in context: A106914 A337924 A049190 * A158314 A249011 A261533
KEYWORD
nonn
AUTHOR
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 April 21 09:27 EDT 2024. Contains 371851 sequences. (Running on oeis4.)