A368990 - OEIS

%I #7 Jan 11 2024 20:04:33

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

%T 0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,

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

%N a(n) = 1 if A005940(1+n) is nondeficient, otherwise 0. Here A005940 is the Doudna sequence.

%H Antti Karttunen, <a href="/A368990/b368990.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) = A294936(A005940(1+n)).

%F a(n) = [A324055(n) <= 0], where [ ] is the Iverson bracket.

%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 A368990(n) = A294936(A005940(1+n));

%Y Cf. A005940, A023196, A294936, A324055, A368991 (partial sums).

%K nonn

%O 0

%A _Antti Karttunen_, Jan 11 2024