OFFSET
1,1
COMMENTS
FORMULA
EXAMPLE
The smallest emirpimes, 15, is not an element, because 15 * 51 = 765 and 7 + 6 + 5 = 18, which is composite.
a(1) = 115 because 115 * 511 = 58765 and 5+8+7+6+5 = 31 is prime.
a(2) = 205 because 205 * 502 = 102910 and 1+0+2+9+1+0 = 13 is prime.
a(3) = 226 because 226 * 622 = 140572 and 1+4+0+5+7+2 = 19 is prime.
MAPLE
read("transforms");
# insert A097393 code here
isA181931 := proc(n)
local R ;
R := digrev(n) ;
if n < R then
if isA097393(n) then
isprime(digsum(n*R)) ;
else
false;
end if;
else
false;
end if;
end proc:
for n from 1 to 2000 do
if isA181931(n) then
printf("%d, ", n) ;
end if;
end do: # R. J. Mathar, Apr 05 2012
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Jonathan Vos Post, Apr 02 2012
EXTENSIONS
More terms from Robert G. Wilson v, Apr 04 2012
STATUS
approved