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 A104090 #9 Oct 29 2024 10:27:15 %S A104090 5,23,113,619,3121,15619,78121,390581,1953109,9765619,48828113, %T A104090 244140613,1220703073,6103515623,30517578121,152587890563, %U A104090 762939453109,3814697265523,19073486328109,95367431640599,476837158203071,2384185791015571,11920928955078089 %N A104090 Largest prime <= 5^n. %F A104090 a(n) = A007917(A000351(n)). - _Paolo Xausa_, Oct 29 2024 %t A104090 NextPrime[5^Range[30] + 1, -1] (* _Paolo Xausa_, Oct 29 2024 *) %o A104090 (PARI) g(n,b) = for(x=0,n,print1(precprime(b^x)",")) %Y A104090 Cf. A014234, A054321, A104088, A104089, A104091-A104094, A003618, A104096. %Y A104090 Cf. A000040, A000351, A007917. %K A104090 easy,nonn %O A104090 1,1 %A A104090 _Cino Hilliard_, Mar 03 2005