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 A280357 #48 Jan 05 2017 03:25:01
%S A280357 53,2927,3733,4139,5347,5351,5953,6761,6763,9791,113111,127123,131129,
%T A280357 137131,149143,179173,191189,211199,223211,223217,223219,233231,
%U A280357 239233,239237,263257,277273,281279,307301,331319,347341,359353,359357,419417,431423,431429,479473
%N A280357 Primes formed from concatenating nextprime(n) and n.
%C A280357 Alternatively: Primes formed from reverse concatenation of n and nextprime(n).
%H A280357 K. D. Bajpai, <a href="/A280357/b280357.txt">Table of n, a(n) for n = 1..10000</a>
%e A280357 53 is in the sequence because it is prime formed from concatenation of 5 and 3, where 5 is next prime after 3.
%e A280357 3733 is in the sequence because it is prime formed from concatenation of 37 and 33, where 37 is next prime after 33.
%t A280357 Select[Table[FromDigits[Join[IntegerDigits[NextPrime[n]], IntegerDigits[n]]],{n,1000}], PrimeQ]
%o A280357 (Magma) [p : n in[1 .. 200] | IsPrime(p) where p is Seqint(Intseq(n) cat Intseq(NextPrime(n)))];
%Y A280357 Cf. A000040, A084667, A084669, A151799, A151800, A280388.
%K A280357 nonn,base
%O A280357 1,1
%A A280357 _K. D. Bajpai_, Jan 04 2017