A102608 - OEIS

%I #4 Mar 30 2012 17:29:21

%S 2,4,11,22,25,26,28,31,32,40,44,47,52,58,70,73,79,80,86,88,89,92,1009,

%T 1010,1013,1016,1045,1051,1070,1079,1081,1088,1090,1097,1111,1135,

%U 1139,1142,1144,1154,1162,1168,1178,1190,1192,1213,1228,1234,1280,1283,1286

%N Numbers L such that 1LM1 is prime and M=L+1.

%e If L=2, then M=3 and 1231 is prime.

%e If L=40, then M=41 and 140411 is prime.

%e If L=88, then M=89 and 188891 is prime.

%t Select[Range[1300], PrimeQ[FromDigits[Flatten[IntegerDigits /@ {1, #, # + 1, 1}]]] &]

%Y Cf. A102606, A102607.

%K nonn,base

%O 1,1

%A _Parthasarathy Nambi_, Jan 29 2005

%E Extended by _Ray Chandler_, Jan 30 2005