|
%I #6 Jan 11 2024 20:04:50
%S 1,1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1,1,0,1,0,0,1,1,1,1,1,1,1,1,1,1,1,0,
%T 0,1,0,0,1,0,0,0,0,0,1,0,0,1,1,0,1,1,0,1,1,1,1,0,0,1,1,1,1,1,1,1,0,1,
%U 0,0,1,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,1,1,1,1,1,1,1,0,1,1,1,0,0,1,1,1,1,1,1,1,0,1,0,0,0,0,1
%N a(n) = A336546(A005940(1+n)).
%H Antti Karttunen, <a href="/A368992/b368992.txt">Table of n, a(n) for n = 0..65537</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%H <a href="/index/Si#SIGMAN">Index entries for sequences related to sigma(n)</a>
%F a(n) = A336546(A005940(1+n)).
%o (PARI)
%o A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
%o A336546(n) = { my(f=factor(n)); (sigma(n)==lcm(vector(#f~,k,sigma(f[k,1]^f[k,2])))); };
%o A368992(n) = A336546(A005940(1+n));
%Y Cf. A005940, A324054, A336546, A368993 (partial sums).
%K nonn
%O 0
%A _Antti Karttunen_, Jan 11 2024
|
