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Primes which are a concatenation of prime(i) and prime(prime(i)) for some i.
1

%I #12 Oct 06 2013 09:27:20

%S 23,1759,2383,41179,61283,71353,83431,127709,2271433,3372269,3532381,

%T 4993559,5033593,5714153,7275503,8876899,9117109,9377351,9717649,

%U 10618513,142711909,157913297,166314107,169314437,170914591,187116073,187716127,190716451,194916901

%N Primes which are a concatenation of prime(i) and prime(prime(i)) for some i.

%H K. D. Bajpai, <a href="/A229814/b229814.txt">Table of n, a(n) for n = 1..10000</a>

%e a(2)=1759: prime(7)= 17 and prime(17)= 59. Concatenating 17 and 59 gives 1759 which is prime.

%e a(4)=41179: prime(13)= 41 and prime(41)= 179. Concatenating 41 and 179 gives 41179 which is prime.

%p K := proc(n) local a,b,d; a :=ithprime(n); b:=ithprime(a); d:=parse(cat(a,b)); if isprime(d) then return (d) end if; end proc:

%p seq(K(n), n=1..1000);

%Y Cf. A030459, A045533.

%K nonn,base,less

%O 1,1

%A _K. D. Bajpai_, Sep 30 2013