login
Primes that are a concatenation of 7, 11 and a prime.
6

%I #10 Jan 24 2020 10:53:13

%S 71119,71129,71143,71147,71153,71161,71167,71171,711131,711163,711173,

%T 711181,711223,711307,711317,711353,711397,711409,711463,711479,

%U 711499,711509,711523,711563,711577,711617,711653,711691,711701,711709,711727

%N Primes that are a concatenation of 7, 11 and a prime.

%H Daniel Starodubtsev, <a href="/A101250/b101250.txt">Table of n, a(n) for n = 1..10000</a>

%H Peter Alfeld, <a href="http://www.math.utah.edu/~alfeld/math/p10000.html">The 10,000 smallest prime numbers</a>.

%e 71119 is a prime concatenated from the primes 7, 11 and 19.

%t Select[ Table[ FromDigits[ Flatten[ IntegerDigits /@ {7, 11, Prime[n]}]], {n, 130}], PrimeQ[ # ] &] (* _Robert G. Wilson v_, Dec 20 2004 *)

%Y Cf. A100607, A101218, A101219, A101249, A101251, A101252.

%K nonn,easy,base

%O 1,1

%A _Parthasarathy Nambi_, Dec 16 2004

%E Extended by _Ray Chandler_ and _Robert G. Wilson v_, Dec 22 2004