%I
%S 131,153,191,233,261,327,341,359,389,407,429,459,489,527,533,579,593,
%T 599,671,683,701,723,731,797,813,869,873,939,981,1083,1097,1109,1143,
%U 1187,1241,1283,1317,1391,1437,1451,1539,1553,1871,1889,1893,2049,2111
%N Numbers n such that the strings n7n and 7n7 are both prime.
%H Daniel Starodubtsev, <a href="/A090264/b090264.txt">Table of n, a(n) for n = 1..10000</a>
%e 131 is a member as 1317131 and 71317 are both prime.
%Y Cf. A090262, A090263, A090265.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Nov 28 2003
%E More terms from mohammed bouayoun (bouyao(AT)wanadoo.fr), Feb 02 2004
