A352249 Emirps that can be written as p*q+p+q where p and q are emirps.

1439, 1511, 3023, 14447, 16127, 16547, 16883, 19763, 30059, 33623, 35099, 35327, 36251, 38219, 39359, 72911, 75239, 76463, 78623, 94559, 96431, 100799, 103511, 107603, 108191, 108863, 110807, 118583, 119039, 119363, 120539, 121727, 126359, 127679, 128879, 129959, 132299, 132887, 134999, 136403

Offset: 1

Author

J. M. Bergot and Robert Israel, Apr 17 2022

Keywords

• nonn
• base

Examples

			a(3) = 3023 is a term because 3023 = 17*167+17+167 and 3023, 17 and 167 are emirps.
		

Links

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

Crossrefs

Cf. A006567.

Programs

Maple

revdigs:= proc(n) local L,i; L:= convert(n,base,10); add(L[-i]*10^(i-1),i=1..nops(L)) end proc:
isemirp:= proc(p) local r;
   if not isprime(p) then return false fi;
   r:= revdigs(p);
   r <> p and isprime(r)
end proc:
E:= select(isemirp, [seq(ithprime(i),i=1..10^4)]):
nE:= nops(E): N:= E[1]*E[-1]+E[1]+E[-1]:
S:= {}:
for i from 1 to nE do
  for j from i+1 to nE do
    x:= E[i]*(E[j]+1)+E[j];
    if x > N then break fi;
    if isemirp(x) then S:= S union {x} fi;
od od:
sort(convert(S,list));