A304480 - OEIS

%I #21 May 24 2020 11:22:37

%S 1,3,25,25,241,241,505,505,505,505,505,505,65521,65521,65521,65521,

%T 65521,65521,65521,65521,65521,65521,65521,65521,131041,131041,131041,

%U 131041,131041,131041,171865,171865,171865,171865,171865,171865,138181681,138181681,138181681,138181681,138181681,138181681

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

%H Seiichi Manyama, <a href="/A304480/b304480.txt">Table of n, a(n) for n = 1..5000</a>

%H Project Euler, <a href="https://projecteuler.net/problem=533">Problem 533 - Minimum values of the Carmichael function</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Carmichael_function">Carmichael function</a>

%o (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 lista(nn) = {v = read("v002322.txt"); for (n=1, nn, print1(minvl(n, v), ", "););}

%Y Cf. A002174, A002322, A002396, A141162, A143407, A335116, A335117.

%K nonn

%O 1,2

%A _Michel Marcus_, May 13 2018

%E a(32) and beyond from _Seiichi Manyama_, May 24 2020