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 A381131 #8 Mar 04 2025 23:20:20
%S A381131 1,2,3,2,5,2,7,2,3,2,11,3,13,2,3,2,17,2,19,2,3,2,23,3,5,2,3,2,29,2,31,
%T A381131 2,3,2,5,2,37,2,3,5,41,2,43,2,5,2,47,3,7,2,3,2,53,2,5,7,3,2,59,3,61,2,
%U A381131 7,2,5,2,67,2,3,2,71,2,73,2,3,2,7,2,79,5
%N A381131 If n = (p_1^e_1)*(p_2^e_2)*(p_3^e_3)*... and min(p_1^e_1,p_2^e_2,...) = p_k^e_k then a(n) = p_k, a(1) = 1.
%t A381131 Table[Exp[MangoldtLambda[Min @@ (#[[1]]^#[[2]] & /@ FactorInteger[n])]], {n, 80}]
%o A381131 (PARI) a(n) = if (n==1, 1, my(f=factor(n), v=vector(#f~, k, f[k,1]^f[k,2]), m=vecmin(v), i=select(x->(x==m), v, 1)); f[i[1], 1]); \\ _Michel Marcus_, Feb 19 2025
%Y A381131 Cf. A020639, A034684, A088387, A381132, A381133.
%K A381131 nonn
%O A381131 1,2
%A A381131 _Ilya Gutkovskiy_, Feb 14 2025