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 A134532 #15 Jun 24 2024 08:48:43
%S A134532 1,2,4,5,6,7,13,19,20,22,26,27,29,33,34,36,41,43,44,50,54,55,58,59,60,
%T A134532 66,69,70,74,75,81,85,91,95,97,99,100,101,110,112,125,127,129,131,133,
%U A134532 134,136,142,143,145,146,148,153,156,157,163,165,178,187,189,190,196
%N A134532 Numbers k such that the sum of the digits of 5^k is prime.
%H A134532 Vincenzo Librandi, <a href="/A134532/b134532.txt">Table of n, a(n) for n = 1..1000</a>
%e A134532 5^2=25 and 2+5=7 is prime.
%p A134532 P:=proc(k) if isprime(convert(convert(5^k,base,10),`+`)) then k; fi; end: seq(P(n),n=1..200);
%t A134532 a={};For[n=1, n<200, n++, If[PrimeQ[Plus@@IntegerDigits[5^n]], AppendTo[a, n]]];a (* _Vincenzo Librandi_, Apr 17 2013 *)
%Y A134532 Cf. A076203, A134533, A134534, A134535.
%K A134532 easy,nonn,base
%O A134532 1,2
%A A134532 _Paolo P. Lava_ and _Giorgio Balzarotti_, Oct 30 2007
%E A134532 Corrected name and new Maple code by_Paolo P. Lava_, Jun 24 2024