%I #14 Feb 16 2020 20:56:01

%S 115,205,226,289,335,497,667,718,1027,1057,1079,1135,1141,1154,1195,

%T 1234,1243,1247,1286,1315,1322,1343,1357,1379,1387,1402,1415,1466,

%U 1469,1502,1513,1514,1538,1658,1679,1691,1703,1765,1769,1774,1817,1843,1882,1927,1937,1942

%N Lesser of emirpimes pairs the product of whose members has prime digital sum.

%C This is to A210547 (Lesser of emirp pairs whose members have prime digital products) as emirpimes A097393 are to emirps A006567 and as A007953 (digital sums) are to A007954 (digital products).

%F {a(n) = {k in A097393, k < R(k), such that A007953(k * R(k)) is prime} = {k in A097393 such that A007953(k * A004086(k)) is in A000040}.

%e The smallest emirpimes, 15, is not an element, because 15 * 51 = 765 and 7 + 6 + 5 = 18, which is composite.

%e a(1) = 115 because 115 * 511 = 58765 and 5+8+7+6+5 = 31 is prime.

%e a(2) = 205 because 205 * 502 = 102910 and 1+0+2+9+1+0 = 13 is prime.

%e a(3) = 226 because 226 * 622 = 140572 and 1+4+0+5+7+2 = 19 is prime.

%p read("transforms");

%p # insert A097393 code here

%p isA181931 := proc(n)

%p local R ;

%p R := digrev(n) ;

%p if n < R then

%p if isA097393(n) then

%p isprime(digsum(n*R)) ;

%p else

%p false;

%p end if;

%p else

%p false;

%p end if;

%p end proc:

%p for n from 1 to 2000 do

%p if isA181931(n) then

%p printf("%d,",n) ;

%p end if;

%p end do: # _R. J. Mathar_, Apr 05 2012

%Y Cf. A001358, A004086, A007953, A007954, A097393, A210547.

%K nonn,base,easy

%O 1,1

%A _Jonathan Vos Post_, Apr 02 2012

%E More terms from _Robert G. Wilson v_, Apr 04 2012