This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A154963 #15 Sep 08 2022 08:45:40 %S A154963 2,17,23,41,61,71,83,127,227,337,353,499,503,571,727,887,911,937,971, %T A154963 1061,1427,1579,1663,1693,1709,1871,1877,1907,1949,1973,2017,2063, %U A154963 2081,2239,2339,2393,2467,2713,2797,2939,2999,3181,3271,3463,3643,3659,3677 %N A154963 Primes p such that the concatenation of p and prime(p) is prime. %H A154963 Vincenzo Librandi, <a href="/A154963/b154963.txt">Table of n, a(n) for n = 1..1000</a> %e A154963 Concatenation of prime 2 and second prime 3 is the prime 23, hence 2 is in the sequence. %e A154963 Concatenation of prime 23 and 23rd prime 83 is the prime 2383, hence 23 is in the sequence. %t A154963 A154963 = Select[ Prime[ Range[ 550 ] ], PrimeQ[ FromDigits[ Join[ IntegerDigits[ # ], IntegerDigits[ Prime[ # ] ] ] ] ] & ] (* _Alonso del Arte_ Nov 12 2009 *) %o A154963 (Magma) [ p: p in PrimesUpTo(3700) | IsPrime(StringToInteger(IntegerToString(p) cat IntegerToString(NthPrime(p)))) ]; %Y A154963 Cf. A045532, A155032 (resulting primes). %K A154963 nonn,base,easy,less %O A154963 1,1 %A A154963 _Juri-Stepan Gerasimov_, Jan 18 2009 %E A154963 Edited and extended beyond a(3) by _Klaus Brockhaus_, Jan 20 2009