A379476 a(n) = 1 if A326057(n) > 1, otherwise 0, where A326057(n) = gcd(A003961(n)-2n, A003961(n)-sigma(n)).

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions.

Index entries for sequences related to prime indices in the factorization of n.

Index entries for sequences related to sigma(n).

Formula

a(n) >= A379475(n).

Prog

(PARI)
A003961(n) = { my(f=factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A326057(n) = { my(u=A003961(n)); gcd(u-(2*n), u-sigma(n)); };
A379476(n) = (A326057(n)>1);

Crossrefs

Characteristic function of A379477.

Cf. A000203, A003961, A252748, A286385, A326057, A379475.

Sequence in context: A144195 A226464 A288665 * A011759 A316345 A118952

Adjacent sequences: A379473 A379474 A379475 * A379477 A379478 A379479

Keyword

nonn

Author

Antti Karttunen, Dec 23 2024

Status

approved