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 A104359 #26 Feb 21 2023 04:25:54 %S A104359 1,5,11,59,179,1259,229,7559,37799,415799,17569,71437,18979,62597, %T A104359 1135133999,1646947,445771,277021,5499724229999,2217247573,721381, %U A104359 46313123,29220034833989999,16347569521,5464930609,4939567,319699160368361,2605998587146349,178974179,15701603,116318025830291273,126202964557 %N A104359 Greatest prime factor of A104357(n) = A104350(n) - 1. %H A104359 Tyler Busby, <a href="/A104359/b104359.txt">Table of n, a(n) for n = 2..159</a> (terms 2..74 from Amiram Eldar, terms 75..145 from Max Alekseyev) %H A104359 Reinhard Zumkeller, <a href="/A104350/a104350.txt">Products of largest prime factors of numbers <= n</a> %F A104359 a(n) = A006530(A104357(n)). %t A104359 a[n_] := FactorInteger[-1 + Product[FactorInteger[k][[-1, 1]], {k, 1, n}]][[-1, 1]]; Array[a, 50, 2] (* _Amiram Eldar_, Feb 12 2020 *) %o A104359 (PARI) gpf(n) = if (n==1, 1, vecmax(factor(n)[,1])); \\ A006530 %o A104359 a(n) = gpf(prod(i=2, n, gpf(i))-1); \\ _Michel Marcus_, Feb 21 2023 %Y A104359 Cf. A006530, A002582, A002584, A104350, A104357, A104358, A104360, A104361, A104362, A104363, A104364, A104367. %K A104359 nonn %O A104359 2,2 %A A104359 _Reinhard Zumkeller_, Mar 06 2005