OFFSET
1,1
COMMENTS
Primes p that can be divided in three parts differing by at most 1 with p + the product of the parts prime.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(3) = 11 is a term because 11 = 3+4+4 with 11+3*4*4 = 59 prime.
MAPLE
filter:= proc(p) local a, t;
if not isprime(p) then return false fi;
if p mod 3 = 1 then a:= (p-1)/3; t:= p+a^2*(a+1) else a:= (p-2)/3; t:= p+a*(a+1)^2 fi;
isprime(t)
end proc:
select(filter, [2, seq(i, i=5..2000, 2)]);
MATHEMATICA
q[p_] := Module[{r = Mod[p, 3], a}, a = (p-r)/3; r > 0 && PrimeQ[p+a*(a+1)*(a+r-1)]]; Select[Prime[Range[300]], q] (* Amiram Eldar, Jul 22 2022 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
J. M. Bergot and Robert Israel, Jul 22 2022
STATUS
approved