A378606 Dirichlet convolution of A046692 and A003961, where A046692 is the Dirichlet inverse of sigma, and A003961 is fully multiplicative with a(prime(i)) = prime(i+1).

1, 0, 1, 2, 1, 0, 3, 6, 8, 0, 1, 2, 3, 0, 1, 18, 1, 0, 3, 2, 3, 0, 5, 6, 12, 0, 40, 6, 1, 0, 5, 54, 1, 0, 3, 16, 3, 0, 3, 6, 1, 0, 3, 2, 8, 0, 5, 18, 40, 0, 1, 6, 5, 0, 1, 18, 3, 0, 1, 2, 5, 0, 24, 162, 3, 0, 3, 2, 5, 0, 1, 48, 5, 0, 12, 6, 3, 0, 3, 18, 200, 0, 5, 6, 1, 0, 1, 6, 7, 0, 9, 10, 5, 0, 3, 54, 3, 0, 8, 24

Offset

1,4

Links

Antti Karttunen, Table of n, a(n) for n = 1..20000

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

Index entries for sequences related to sigma(n).

Formula

a(n) = Sum_{d|n} A046692(d)*A003961(n/d).

a(n) = Sum_{d|n} A008683(d)*A349387(n/d).

Prog

(PARI)
A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
A046692(n) = { my(f=factor(n)~); prod(i=1, #f, if(1==f[2, i], -(f[1, i]+1), if(2==f[2, i], f[1, i], 0))); };
A378606(n) = sumdiv(n, d, A046692(d)*A003961(n/d));

Crossrefs

Cf. A003961, A008683, A016825, A046692, A349387 (inverse Möbius transform), A378607 (Dirichlet inverse).

Sequence in context: A244117 A263426 A378607 * A357103 A278882 A153007

Adjacent sequences: A378603 A378604 A378605 * A378607 A378608 A378610

Keyword

nonn,mult,new

Author

Antti Karttunen, Dec 11 2024

Status

approved