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 A080103 #10 Mar 26 2025 08:28:27 %S A080103 4,1,9,1,16,1,1,27,1,32,1,1,1,49,1,1,64,1,1,1,81,1,1,1,1,1,1,1,125, %T A080103 128,1,1,1,1,1,1,1,169,1,1,1,1,1,1,1,1,1,1,1,1,1,243,256,1,1,1,1,1,1, %U A080103 289,1,1,1,1,1,1,343,1,1,1,361,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 %N A080103 Greatest prime power in all composite numbers between n-th prime and next prime, a(n) = 1 if no such prime power exists. %H A080103 Amiram Eldar, <a href="/A080103/b080103.txt">Table of n, a(n) for n = 2..10000</a> %e A080103 There are two prime powers between 7 = A000040(4) and 11 = A000040(5): 8 = 2^3 and 9 = 3^2, therefore a(4) = 9, A080102(4) = 8 and A080101(4) = 2. %t A080103 a[n_] := SelectFirst[Range[Prime[n + 1] - 1, Prime[n] + 1, -1], PrimePowerQ, 1]; Array[a, 100, 2] (* _Amiram Eldar_, Mar 26 2025 *) %Y A080103 Cf. A080101, A080102, A025475, A000961. %K A080103 nonn %O A080103 2,1 %A A080103 _Reinhard Zumkeller_, Jan 28 2003