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 A378159 #8 Nov 19 2024 00:59:13
%S A378159 1,3,11,53,3,13,11,3,1468457,11,3,1373,34361893981,3,17713,2130617,3,
%T A378159 11,13,3,11,617,3,37,11,3,179,14633,3,76463,97,3,337,1049,3,11,
%U A378159 7237598635049,3,67,11,3,22742406079421034331584846001936724930824184898296683,11,3,13
%N A378159 The least prime dividing A000255(n); a(1) = 1.
%H A378159 Amiram Eldar, <a href="/A378159/b378159.txt">Table of n, a(n) for n = 1..137</a>
%F A378159 a(n) = A020639(A000255(n)).
%F A378159 a(n) = A000255(n) if and only if n+2 is a term of A301423.
%F A378159 a(3*n-1) = 3.
%t A378159 FactorInteger[#][[1, 1]] & /@ Table[Subfactorial[n + 2]/(n + 1), {n, 1, 44}]
%o A378159 (PARI) lpf(n) = if(n == 1, 1, factor(n)[1,1]);
%o A378159 lista(nmax) = {my(s = 1); for(n = 1, nmax, s = (n * (n+2) * s + (-1)^n)/(n+1); print1(lpf(s), ", "));}
%Y A378159 Cf. A000255, A020639, A301423, A378157.
%K A378159 nonn
%O A378159 1,2
%A A378159 _Amiram Eldar_, Nov 18 2024