A368699 a(n) = A354989(A005940(1+n)).

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0

Offset

0

Links

Antti Karttunen, Table of n, a(n) for n = 0..16384

Index entries for characteristic functions

Formula

a(n) = A354989(A005940(1+n)).

Prog

(PARI)
\\ Slow:
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
A354989(n) = for(m=1, oo, if((m*(m+1))%n==0, return(gcd(n, 1+m)<gcd(n, m))));
A368699(n) = A354989(A005940(1+n));
(PARI)
\\ Use this if A368698 is already computed:
v368698 = readvec("b368698_to.txt"); \\ Prepared with gawk ' { print $2 } ' < b368698.txt > b368698_to.txt
A368698(n) = v368698[1+n];
up_to = #v368698-1;
A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); };
A368699(n) = { my(u=A368698(n), k=A005940(1+n)); return(gcd(k, 1+u)<gcd(k, u)); };

Crossrefs

Cf. A005940, A354989, A368698, A368700 (partial sums).

Sequence in context: A369667 A358773 A044941 * A277151 A277155 A277159

Adjacent sequences: A368696 A368697 A368698 * A368700 A368701 A368702

Keyword

nonn

Author

Antti Karttunen, Jan 11 2024

Status

approved