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 A081811 #16 Jan 13 2025 08:21:46
%S A081811 0,2,3,4,5,2,7,6,6,2,11,3,13,2,3,8,17,2,19,4,3,2,23,3,10,2,9,4,29,2,
%T A081811 31,10,3,2,5,4,37,2,3,5,41,2,43,4,5,2,47,3,14,2,3,4,53,2,5,6,3,2,59,3,
%U A081811 61,2,6,12,5,2,67,4,3,2,71,6,73,2,3,4,7,2,79,5,12,2,83,3,5,2,3,6,89,2,7,4,3
%N A081811 If n = p_1^e_1 * ... * p_k^e_k, p_1 < ... < p_k primes, then a(n) = min{ p_i*e_i }.
%H A081811 Alois P. Heinz, <a href="/A081811/b081811.txt">Table of n, a(n) for n = 1..10000</a>
%p A081811 a:= n-> `if`(n=1, 0, min(seq(i[1]*i[2], i=ifactors(n)[2]))):
%p A081811 seq(a(n), n=1..100); # _Alois P. Heinz_, Jul 19 2020
%t A081811 a[n_] := If[n == 1, 0, Min[Times @@@ FactorInteger[n]]];
%t A081811 Table[a[n], {n, 1, 100}] (* _Jean-François Alcover_, Jan 13 2025 *)
%o A081811 (PARI) a(n)=local(f); if(n==1,0,f=factor(n); vecmin(vector(matsize(f)[1],k,f[k,1]*f[k,2])))
%Y A081811 Cf. A081810 (with max).
%K A081811 nonn
%O A081811 1,2
%A A081811 _Benoit Cloitre_, Apr 10 2003