A378537 - OEIS

%I #13 Dec 05 2024 13:51:52

%S 0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,

%T 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,

%U 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0

%N Characteristic function for primitive Zumkeller numbers.

%C Differs from A341619 at n = 748, 7544, 8228, 10184, ..., A378538.

%H Antti Karttunen, <a href="/A378537/b378537.txt">Table of n, a(n) for n = 1..108045</a>

%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>

%F a(n) = [A083206(n) > 0 and A083206(n) = A378446(n)], where [ ] is the Iverson bracket.

%F a(n) <= A179527(n).

%F a(n) <= A378539(n).

%o (PARI)

%o A378446(n) = sumdiv(n,d,A083206(d));

%o A378537(n) = (A083206(n) && (A083206(n)==A378446(n)));

%o (PARI) A378537(n) = if(!A179527(n), 0, fordiv(n,d,if(d<n && A179527(d), return(0))); (1));

%Y Characteristic function of A180332.

%Y Cf. A083206, A179527, A341619, A378446, A378538, A378539.

%Y Cf. also A378454.

%K nonn,new

%O 1

%A _Antti Karttunen_, Dec 02 2024