cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A346254 Dirichlet inverse of A336849.

Original entry on oeis.org

1, -3, -5, 0, -7, 25, -11, 0, 0, 21, -13, -30, -17, 55, 35, 0, -19, -100, -23, 0, 55, 39, -29, 36, 0, 85, 0, -66, -31, -175, -37, 0, 65, 57, 77, 400, -41, 115, 85, 0, -43, -495, -47, 108, 0, 145, -53, -216, 0, 98, 171, -68, -59, 500, 169, 0, 115, 93, -61, 210, -67, 111, 0, 0, 119, -325, -71, 0, 261, -385, -73, -120, -79, 205, 0, -138
Offset: 1

Views

Author

Antti Karttunen, Jul 19 2021

Keywords

Crossrefs

Cf. A000203, A003961, A003973, A336849, A346255, A346256 (positions of zeros).
Cf. also A346235, A346246, A346248.

Programs

  • PARI
    up_to = 16384;
    DirInverseCorrect(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = (-u[1]*sumdiv(n, d, if(dA003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); }; \\ From A003961
    A336849(n) = { my(u=A003961(n)); (u/gcd(u, sigma(u))); };
    v346254 = DirInverseCorrect(vector(up_to,n,A336849(n)));
    A346254(n) = v346254[n];

Formula

a(n) = A346255(n) - A336849(n).

A346251 Positions of zeros in A346246.

Original entry on oeis.org

192, 1280, 4608, 11520, 28672, 180224, 274428, 288684, 2013440, 3407872
Offset: 1

Views

Author

Antti Karttunen, Jul 19 2021

Keywords

Comments

Applying prime shift (A003961) to these terms gives 3645, 45927, 492075, ..., a subsequence of the positions of zeros in A323910.

Crossrefs

Cf. also A346256.
Showing 1-2 of 2 results.