A261455 - OEIS

%I #11 Aug 21 2015 02:04:26

%S 2,4,13,30,73,82,120,168,227,422,433,451,607,612,798,1527,6958

%N Numbers n such that 1+131*10^(n-1)+100^n is prime.

%C No other terms < 10000.

%e For n=2, 11311 is prime.

%e For n=3, 1013101 is not prime.

%e For n=4, 100131001 is prime.

%o (PARI) isok(n)=isprime(1+131*10^(n-1)+100^n) \\ _Anders Hellström_, Aug 20 2015

%Y Cf. A171411, A171376.

%K nonn,more

%O 1,1

%A _Chai Wah Wu_, Aug 20 2015