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%I #19 Nov 23 2021 18:11:22
%S 0,1,1,3,1,5,1,7,2,9,1,11,1,13,7,15,1,17,1,19,1,21,1,23,2,25,13,27,1,
%T 29,1,31,2,33,17,35,1,37,19,39,1,41,1,43,1,45,1,47,1,49,5,51,1,53,3,
%U 55,2,57,1,59,1,61,31,63,4,65,1,67,17,69,1,71,1,73,37,75,19,77,1,79,1,81,1,83,1,85,43,87,1,89
%N a(n) = (n-1) / A346467(n).
%C Numbers n such that a(n) = 1 are A248614(m)+1 for m > 0. These are all primes together with A317210. The set of these numbers has zero asymptotic density.
%H Antti Karttunen, <a href="/A346468/b346468.txt">Table of n, a(n) for n = 1..20000</a>
%F a(n) = (n-1) / A346467(n).
%F a(n) = (n-1) / A002322(A027642(n-1)).
%t {0}~Join~Array[#/CarmichaelLambda@ Denominator@ BernoulliB@ # &, 89] (* _Michael De Vlieger_, Nov 23 2021 *)
%o (PARI) A346468(n) = if(1==n,0,my(m=1); fordiv(n-1,d,if(isprime(1+d),m = lcm(m,d))); ((n-1)/m));
%Y Cf. A002322, A027642, A248614, A317210, A346467.
%K nonn
%O 1,4
%A _Antti Karttunen_ and _Thomas Ordowski_, Jul 22 2021