OFFSET
1,1
EXAMPLE
4409 = (4397 + 4409 + 4421)/3 = 13227/3 and 4409 = 440*10 + 9.
MAPLE
p:=ithprime: a:=n->`if`(add(p(n-k), k=-1..1)=3*p(n) and modp(p(n), 10) = 9, p(n), NULL): seq(a(n), n=3..8000);
PROG
(GAP) P:=Filtered([1..78000], IsPrime);;
a:=Filtered(List(Filtered(List([0..Length(P)-3], k->List([1..3], j->P[j+k])), i->Sum(i)/3=i[2]), m->m[2]), l-> l mod 10=9);
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Muniru A Asiru, Apr 18 2018
STATUS
approved