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 A104366 #33 Feb 21 2023 07:34:10 %S A104366 2,3,7,13,61,181,13,2521,7561,103,415801,1247401,167,191,211,127,23, %T A104366 40357,1099944846001,349,41,251,37,2243,146100174169950001,103,53, %U A104366 1217,1156675078903494150001,47,2939,251,857,41,547,13127,47,48563,281,1336484560722851,479,373,2179,577670972464621571,17491,1399,97,22893547 %N A104366 Smallest prime factor of A104365(n) = A104350(n) + 1. %C A104366 a(n) = A020639(A104365(n)). %H A104366 Tyler Busby, <a href="/A104366/b104366.txt">Table of n, a(n) for n = 1..170</a> (terms 1..100 from Chai Wah Wu, terms 101..165 from Max Alekseyev) %H A104366 Reinhard Zumkeller, <a href="/A104350/a104350.txt">Products of largest prime factors of numbers <= n</a> %o A104366 (PARI) gpf(n) = if (n==1, 1, vecmax(factor(n)[,1])); \\ A006530 %o A104366 spf(n) = if (n==1, 1, vecmin(factor(n)[,1])); \\ A020639 %o A104366 a(n) = spf(prod(i=2, n, gpf(i))+1); \\ _Michel Marcus_, Feb 21 2023 %Y A104366 Cf. A104367, A104358, A051301, A051342, A104358, A104365, A104367, A104368, A104369, A104370, A104371, A104372. %K A104366 nonn %O A104366 1,1 %A A104366 _Reinhard Zumkeller_, Mar 06 2005 %E A104366 Corrected by _D. S. McNeil_, Dec 10 2010