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.

A063452 Numbers k such that k - mu(k) is prime.

Original entry on oeis.org

2, 6, 14, 30, 38, 42, 62, 66, 70, 74, 78, 102, 130, 138, 158, 190, 194, 222, 238, 278, 282, 310, 314, 366, 390, 398, 418, 422, 430, 438, 442, 458, 462, 498, 510, 542, 570, 598, 606, 614, 618, 642, 646, 658, 662, 674, 682, 734, 742, 758, 770, 786, 798, 822
Offset: 1

Views

Author

Jason Earls, Jul 25 2001

Keywords

Crossrefs

Programs

  • Magma
    [n: n in [1..1000] |IsPrime(n - MoebiusMu(n))]; // Vincenzo Librandi, Jun 26 2018
  • Mathematica
    Select[Range[1, 1000], PrimeQ[# - MoebiusMu[#]] &] (* Vincenzo Librandi, Jun 26 2018 *)
  • PARI
    ok(m)={isprime(m - moebius(m))}
    

A076369 a(n) = n + mu(n), where mu is the Moebius function (A008683).

Original entry on oeis.org

2, 1, 2, 4, 4, 7, 6, 8, 9, 11, 10, 12, 12, 15, 16, 16, 16, 18, 18, 20, 22, 23, 22, 24, 25, 27, 27, 28, 28, 29, 30, 32, 34, 35, 36, 36, 36, 39, 40, 40, 40, 41, 42, 44, 45, 47, 46, 48, 49, 50, 52, 52, 52, 54, 56, 56, 58, 59, 58, 60, 60, 63, 63, 64, 66, 65, 66, 68, 70, 69, 70, 72
Offset: 1

Views

Author

Reinhard Zumkeller and Labos Elemer, Oct 14 2002

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := n + MoebiusMu[n]; Array[a, 100] (* Amiram Eldar, Apr 09 2025 *)
  • PARI
    a(n) = n + moebius(n); \\ Amiram Eldar, Apr 09 2025

Formula

a(n) = n + mu(m) = A000027(n) + A008683(n).
a(n) = n iff n is not squarefree: a(A013929(k)) = A013929(k) and a(A005117(k)) <> A005117(k).

A075431 Primes of the form n+mu(n), where mu is the Moebius function (A008683).

Original entry on oeis.org

2, 7, 11, 23, 29, 41, 47, 59, 83, 101, 107, 109, 113, 137, 167, 173, 179, 181, 211, 227, 229, 257, 263, 281, 317, 331, 347, 353, 359, 373, 383, 401, 409, 433, 463, 467, 479, 503, 547, 563, 571, 587, 601, 617, 641, 653, 677, 691, 709, 719, 761, 821, 829, 839, 853
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 15 2002

Keywords

Comments

Subsequence of A075430.

Crossrefs

Programs

  • PARI
    isok(p)={isprime(p) && (moebius(p+1) == -1 || moebius(p-1) == 1)} \\ Andrew Howroyd, Apr 20 2021

Extensions

Terms a(41) and beyond from Andrew Howroyd, Apr 20 2021
Showing 1-3 of 3 results.