

A346416


Primes p such that the greatest perimeter of a triangle with prime sides including p and the next prime is prime.


1



5, 11, 13, 17, 19, 37, 41, 43, 47, 59, 71, 89, 103, 109, 113, 137, 139, 149, 163, 167, 173, 179, 181, 241, 269, 313, 337, 379, 389, 401, 491, 499, 521, 547, 557, 569, 587, 599, 607, 613, 617, 631, 643, 673, 677, 701, 739, 773, 787, 811, 839, 877, 883, 887, 929, 941, 953, 971, 977, 983, 1019, 1021
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OFFSET

1,1


COMMENTS

If p is prime and q is the next prime, the greatest perimeter is p+q+r where r is the greatest prime < p+q.


LINKS

Robert Israel, Table of n, a(n) for n = 1..10000


EXAMPLE

a(3) = 13 is a term because the next prime is 17, the greatest prime < 13+17 is 29, and 13+17+29 = 59 is prime.


MAPLE

f:= proc(n) local p, q, r, s;
p:= ithprime(n);
q:= ithprime(n+1);
r:= prevprime(p+q);
s:= p+q+r;
if isprime(p+q+r) then return p fi
end proc:
map(f, [$1..500]);


CROSSREFS

Cf. A096215.
Sequence in context: A090320 A085909 A288450 * A272446 A307390 A104110
Adjacent sequences: A346413 A346414 A346415 * A346417 A346418 A346419


KEYWORD

nonn


AUTHOR

J. M. Bergot and Robert Israel, Jul 15 2021


STATUS

approved



