login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A340821 a(n) is the least prime p such that prime(n)*p + prime(n+1)*q + prime(n+2)*r is prime where p,q,r are consecutive primes. 2
3, 3, 3, 61, 3, 3, 17, 3, 5, 13, 3, 29, 17, 13, 3, 5, 7, 19, 23, 5, 11, 3, 3, 23, 3, 3, 3, 19, 19, 7, 7, 23, 43, 5, 7, 67, 7, 7, 11, 19, 29, 3, 3, 7, 19, 5, 3, 3, 23, 3, 29, 7, 17, 13, 37, 13, 7, 3, 23, 3, 3, 19, 53, 29, 17, 3, 3, 43, 7, 43, 5, 11, 5, 7, 19, 19, 19, 163, 3, 3, 3, 7, 5, 31, 17, 19 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Robert Israel, Table of n, a(n) for n = 2..10000

EXAMPLE

a(3) = 3 where 5*3 + 7*5 + 11*7 = 167 is prime.

MAPLE

f:= proc(n) local k, t;

  for k from 1 do

     t:=ithprime(n)*ithprime(k) + ithprime(n+1)*ithprime(k+1) + ithprime(n+2)*ithprime(k+2);

     if isprime(t) then return ithprime(k) fi;

  od

end proc:

map(f, [$2..100]);

CROSSREFS

Cf. A340817.

Sequence in context: A124013 A135584 A174538 * A091323 A174641 A217671

Adjacent sequences:  A340818 A340819 A340820 * A340822 A340823 A340824

KEYWORD

nonn

AUTHOR

J. M. Bergot and Robert Israel, Jan 22 2021

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 October 24 08:42 EDT 2021. Contains 348217 sequences. (Running on oeis4.)