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 1-5 of 5 results.

A084301 a(n) = sigma(n) mod 6.

Original entry on oeis.org

1, 3, 4, 1, 0, 0, 2, 3, 1, 0, 0, 4, 2, 0, 0, 1, 0, 3, 2, 0, 2, 0, 0, 0, 1, 0, 4, 2, 0, 0, 2, 3, 0, 0, 0, 1, 2, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 4, 3, 3, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 2, 1, 0, 0, 2, 0, 0, 0, 0, 3, 2, 0, 4, 2, 0, 0, 2, 0, 1, 0, 0, 2, 0, 0, 0, 0, 0, 0, 4, 0, 2, 0, 0, 0, 2, 3, 0, 1, 0, 0, 2, 0, 0
Offset: 1

Views

Author

Labos Elemer, Jun 02 2003

Keywords

Crossrefs

Sequences sigma(n) mod k: A053866 (k=2), A074941 (k=3), A105824 (k=4), A105825 (k=5), A084301 (k=6), A105826 (k=7), A105827 (k=8).
Cf. A074627 (locations of 0), A074628 (locations of 2), A067051 (locations of 3), A074630 (locations of 4), A074384 (locations of 5).

Programs

Formula

a(n) = A010875(A000203(n)). - Antti Karttunen, Nov 07 2017

A074942 a(n) = phi(n) mod 3.

Original entry on oeis.org

1, 1, 2, 2, 1, 2, 0, 1, 0, 1, 1, 1, 0, 0, 2, 2, 1, 0, 0, 2, 0, 1, 1, 2, 2, 0, 0, 0, 1, 2, 0, 1, 2, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 2, 0, 1, 1, 1, 0, 2, 2, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 2, 0, 2, 0, 2, 2, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 2, 0, 1, 1, 0, 1, 0, 2, 1, 1, 0, 0, 2, 0, 1, 0, 2, 0, 0, 0, 1, 1, 2, 0, 0, 0
Offset: 1

Views

Author

Benoit Cloitre, Oct 04 2002

Keywords

Crossrefs

Programs

  • Magma
    [EulerPhi(n) mod 3: n in [1..110]]; // Vincenzo Librandi, Sep 04 2015
  • Mathematica
    Table[Mod[EulerPhi[n], 3], {n, 100}] (* Vincenzo Librandi, Sep 04 2015 *)
  • PARI
    a(n)=eulerphi(n)%3
    

Formula

a(n) = A000010(n) mod 3.
a(n) = A010872(A000010(n)). - Michel Marcus, Sep 05 2015

A353768 a(n) = phi(n) mod 4; Euler totient function reduced modulo 4.

Original entry on oeis.org

1, 1, 2, 2, 0, 2, 2, 0, 2, 0, 2, 0, 0, 2, 0, 0, 0, 2, 2, 0, 0, 2, 2, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 2, 2, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2
Offset: 1

Views

Author

Antti Karttunen, May 15 2022

Keywords

Crossrefs

Cf. A000010, A010873, A066499 (positions of 2's), A172019 (of 0's).
Cf. also A074942, A261872, A084300, and also A105824.

Programs

  • PARI
    A353768(n) = (eulerphi(n)%4);

Formula

a(n) = A010873(A000010(n)).

A261872 a(n) = phi(n) mod 5, where phi is the Euler totient function.

Original entry on oeis.org

1, 1, 2, 2, 4, 2, 1, 4, 1, 4, 0, 4, 2, 1, 3, 3, 1, 1, 3, 3, 2, 0, 2, 3, 0, 2, 3, 2, 3, 3, 0, 1, 0, 1, 4, 2, 1, 3, 4, 1, 0, 2, 2, 0, 4, 2, 1, 1, 2, 0, 2, 4, 2, 3, 0, 4, 1, 3, 3, 1, 0, 0, 1, 2, 3, 0, 1, 2, 4, 4, 0, 4, 2, 1, 0, 1, 0, 4, 3, 2, 4, 0, 2, 4, 4, 2, 1, 0, 3, 4, 2, 4, 0, 1, 2, 2, 1, 2, 0, 0, 0, 2, 2, 3, 3
Offset: 1

Views

Author

Vincenzo Librandi, Sep 04 2015

Keywords

Crossrefs

Programs

  • Magma
    [EulerPhi(n) mod 5: n in [1..110]];
    
  • Mathematica
    Table[Mod[EulerPhi[n], 5], {n, 110}]
  • PARI
    a(n) = eulerphi(n) % 5; \\ Michel Marcus, Sep 05 2015

Formula

a(n) = A000010(n) mod 5 = A010874(A000010(n)).

Extensions

More terms from Antti Karttunen, Dec 04 2017

A084302 Remainder of tau(n) modulo 6.

Original entry on oeis.org

1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 0, 2, 4, 4, 5, 2, 0, 2, 0, 4, 4, 2, 2, 3, 4, 4, 0, 2, 2, 2, 0, 4, 4, 4, 3, 2, 4, 4, 2, 2, 2, 2, 0, 0, 4, 2, 4, 3, 0, 4, 0, 2, 2, 4, 2, 4, 4, 2, 0, 2, 4, 0, 1, 4, 2, 2, 0, 4, 2, 2, 0, 2, 4, 0, 0, 4, 2, 2, 4, 5, 4, 2, 0, 4, 4, 4, 2, 2, 0, 4, 0, 4, 4, 4, 0, 2, 0, 0, 3, 2, 2, 2, 2, 2
Offset: 1

Views

Author

Labos Elemer, Jun 02 2003

Keywords

Comments

The sums of the first 10^k terms, for k = 1, 2, ..., are 27, 236, 2275, 22166, 220070, 2195376, 21933228, 219259514, 2192385128, 21923168052, ... . Conjecture: the asymptotic mean of this sequence is 3*zeta(3)/zeta(2) = 3 * A253905 = 2.192288... . The conjecture is true if A211337 and A211338 have an equal asymptotic density (see also A059269). - Amiram Eldar, Jul 11 2024

Crossrefs

Programs

Formula

a(n) = A000005(n) modulo 6.
Showing 1-5 of 5 results.