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A304480 a(n) is the least m such that lambda(k) >= n for all k >= m where lambda is A002322, the Carmichael lambda function.

%I A304480 #21 May 24 2020 11:22:37
%S A304480 1,3,25,25,241,241,505,505,505,505,505,505,65521,65521,65521,65521,
%T A304480 65521,65521,65521,65521,65521,65521,65521,65521,131041,131041,131041,
%U A304480 131041,131041,131041,171865,171865,171865,171865,171865,171865,138181681,138181681,138181681,138181681,138181681,138181681
%N A304480 a(n) is the least m such that lambda(k) >= n for all k >= m where lambda is A002322, the Carmichael lambda function.
%H A304480 Seiichi Manyama, <a href="/A304480/b304480.txt">Table of n, a(n) for n = 1..5000</a>
%H A304480 Project Euler, <a href="https://projecteuler.net/problem=533">Problem 533 - Minimum values of the Carmichael function</a>
%H A304480 Wikipedia, <a href="http://en.wikipedia.org/wiki/Carmichael_function">Carmichael function</a>
%o A304480 (PARI) minvl(n, v) = {vgt = select(x->(x>=n), v, 1); first = vgt[1]; vgtd = vector(#vgt-1, k, vgt[k+1] - vgt[k]); vgtdr = Vecrev(vgtd); vokdiff = select(x->x!=1, vgtdr, 1); if (#vokdiff, #v - vokdiff[1]+1, first);}
%o A304480 lista(nn) = {v = read("v002322.txt"); for (n=1, nn, print1(minvl(n, v), ", "););}
%Y A304480 Cf. A002174, A002322, A002396, A141162, A143407, A335116, A335117.
%K A304480 nonn
%O A304480 1,2
%A A304480 _Michel Marcus_, May 13 2018
%E A304480 a(32) and beyond from _Seiichi Manyama_, May 24 2020