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 1-3 of 3 results.

A345930 a(n) = A344756(A276086(n)).

Original entry on oeis.org

1, 1, 1, 2, 7, 1, 1, 1, 1, 13, 41, 2, 9, 11, 37, 2, 47, 3, 11, 7, 43, 19, 53, 4, 13, 17, 49, 11, 59, 1, 1, 1, 1, 17, 55, 1, 1, 1, 1, 106, 317, 19, 73, 92, 289, 127, 359, 13, 87, 113, 331, 148, 401, 11, 101, 134, 373, 169, 443, 2, 11, 13, 47, 2, 61, 17, 69, 86, 277, 121, 347, 2, 83, 107, 319, 2, 389, 31, 97, 128, 19
Offset: 1

Views

Author

Antti Karttunen, Jul 19 2021

Keywords

Crossrefs

Cf. also A342002, A346474, A346475 (compare the scatter plots).

Programs

Formula

a(n) = A344756(A276086(n)).
a(n) = A327860(n) / A346469(n) = A327860(n) / gcd(A327860(n), A329029(n)).

A344696 a(n) = sigma(n) / gcd(sigma(n), A001615(n)).

Original entry on oeis.org

1, 1, 1, 7, 1, 1, 1, 5, 13, 1, 1, 7, 1, 1, 1, 31, 1, 13, 1, 7, 1, 1, 1, 5, 31, 1, 10, 7, 1, 1, 1, 21, 1, 1, 1, 91, 1, 1, 1, 5, 1, 1, 1, 7, 13, 1, 1, 31, 57, 31, 1, 7, 1, 10, 1, 5, 1, 1, 1, 7, 1, 1, 13, 127, 1, 1, 1, 7, 1, 1, 1, 65, 1, 1, 31, 7, 1, 1, 1, 31, 121, 1, 1, 7, 1, 1, 1, 5, 1, 13, 1, 7, 1, 1, 1, 21, 1, 57, 13
Offset: 1

Views

Author

Antti Karttunen, May 26 2021

Keywords

Comments

This is not multiplicative. The first point where a(m*n) = a(m)*a(n) does not hold for coprime m and n is 108 = 4*27, where a(108) = 35, although a(4) = 7 and a(27) = 10. See A344702.

Crossrefs

Cf. A000203, A001615, A005117 (positions of ones), A344695, A344697, A344698, A344702.
Cf. also A344756.

Programs

  • PARI
    A001615(n) = if(1==n,n, my(f=factor(n)); prod(i=1, #f~, f[i, 1]^f[i, 2] + f[i, 1]^(f[i, 2]-1))); \\ After code in A001615
    A344696(n) = { my(u=sigma(n)); (u/gcd(u,A001615(n))); };

Formula

a(n) = A000203(n) / A344695(n).

A344757 a(n) = A069359(n) / gcd(A003415(n), A069359(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 1, 1, 1, 1, 5, 1, 7, 1, 1, 1, 5, 1, 1, 1, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 13, 8, 1, 1, 5, 1, 7, 1, 15, 1, 5, 1, 9, 1, 1, 1, 31, 1, 1, 10, 1, 1, 1, 1, 19, 1, 1, 1, 5, 1, 1, 8, 21, 1, 1, 1, 7, 1, 1, 1, 41, 1, 1, 1, 13, 1, 31, 1, 25, 1, 1, 1, 5, 1, 9, 14, 1, 1, 1, 1, 15
Offset: 2

Views

Author

Antti Karttunen, May 28 2021

Keywords

Crossrefs

Programs

Formula

a(n) = A069359(n) / A340070(n) = A069359(n) / gcd(A003415(n), A069359(n)).
Showing 1-3 of 3 results.