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 A328457 #9 Feb 23 2023 15:30:26 %S A328457 0,1,1,1,1,2,1,1,1,1,1,3,1,1,1,1,1,2,1,2,1,1,1,3,1,1,1,1,1,2,1,1,1,1, %T A328457 1,3,1,1,1,2,1,2,1,1,1,1,1,3,1,1,1,1,1,2,1,2,1,1,1,5,1,1,1,1,1,2,1,1, %U A328457 1,1,1,3,1,1,1,1,1,2,1,2,1,1,1,3,1,1,1,1,1,2,1,1,1,1,1,3,1,1,1,2,1,2,1,1,1 %N A328457 Length of the longest run of divisors > 1 of n. %H A328457 Antti Karttunen, <a href="/A328457/b328457.txt">Table of n, a(n) for n = 1..100000</a> %t A328457 Table[If[n==1,0,Max@@Length/@Split[Rest[Divisors[n]],#2==#1+1&]],{n,100}] %o A328457 (PARI) A328457(n) = { my(rl=0,pd=0,m=0); fordiv(n, d, if(d>1, if(d>(1+pd), m = max(m,rl); rl=0); pd=d; rl++)); max(m,rl); }; \\ _Antti Karttunen_, Feb 23 2023 %Y A328457 Records occur at A328448. %Y A328457 Positions of 0's and 1's are A088725. %Y A328457 The version that looks at all divisors (including 1) is A055874. %Y A328457 The number of successive pairs of divisors > 1 of n is A088722(n). %Y A328457 The Heinz number of the multiset of run-lengths of divisors of n is A328166(n). %Y A328457 The longest run of nontrivial divisors of n is A328458(n). %Y A328457 Cf. A000005, A027750, A129308, A181063, A199970, A328162, A328195, A328449, A360128. %K A328457 nonn %O A328457 1,6 %A A328457 _Gus Wiseman_, Oct 16 2019 %E A328457 Data section extended up to a(105) by _Antti Karttunen_, Feb 23 2023