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 A048525 #13 Dec 02 2024 15:17:34
%S A048525 277,1559,5779,7489,11279,15091,22093,37811,43579,46279,48541,49957,
%T A048525 53479,54751,60589,68473,72883,74821,83621,85621,90793,91921,93901,
%U A048525 97501,107981,110899,111799,120193,153379,157739,170299,180731,184441
%N A048525 Primes for which only three iterations of 'Prime plus its digit sum equals a prime' are possible.
%H A048525 Lars Blomberg, <a href="/A048525/b048525.txt">Table of n, a(n) for n = 1..10000</a>
%e A048525 prime 7489 -> 7489 + (7+4+8+9) = prime 7517 -> 7517 + (7+5+1+7) = prime 7537 -> 7537 + (7+5+3+7) = prime 7559 -> next iteration yields composite 7585.
%t A048525 tiQ[p_]:=Boole[PrimeQ[NestList[#+Total[IntegerDigits[#]]&,p,4]]]=={1,1,1,1,0}; Select[Prime[Range[20000]],tiQ] (* _Harvey P. Dale_, Dec 02 2024 *)
%Y A048525 Cf. A047791, A048519.
%K A048525 nonn,base
%O A048525 1,1
%A A048525 _Patrick De Geest_, May 15 1999