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.

A079871 a(1)=1 and for n>1: ceiling(n^(1/Omega(n)))^Omega(n), where Omega(n) is the total number of prime factors of n (A001222).

Original entry on oeis.org

1, 2, 3, 4, 5, 9, 7, 8, 9, 16, 11, 27, 13, 16, 16, 16, 17, 27, 19, 27, 25, 25, 23, 81, 25, 36, 27, 64, 29, 64, 31, 32, 36, 36, 36, 81, 37, 49, 49, 81, 41, 64, 43, 64, 64, 49, 47, 243, 49, 64, 64, 64, 53, 81, 64, 81, 64, 64, 59, 81, 61, 64, 64, 64, 81, 125, 67, 125, 81, 125, 71
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 13 2003

Keywords

Crossrefs

Programs

  • Mathematica
    A079871[n_] := If [n == 1, 1, Ceiling[n^(1/#)]^# & [PrimeOmega[n]]];
    Array[A079871, 100] (* Paolo Xausa, Oct 27 2024 *)
  • PARI
    a(n) = if (n==1, 1, ceil(n^(1/bigomega(n)))^bigomega(n)); \\ Michel Marcus, May 31 2016

Formula

a(n) = A079870(n)^A001222(n).
a(n) >= A079869(n); A020639(n) <= a(n) <= A006530(n);
a(m) = m = A079869(m) iff m is a prime power (A000961).

A079870 a(1)=1 and for n>1: ceiling(n^(1/Omega(n))), where Omega(n) is the total number of prime factors of n (A001222).

Original entry on oeis.org

1, 2, 3, 2, 5, 3, 7, 2, 3, 4, 11, 3, 13, 4, 4, 2, 17, 3, 19, 3, 5, 5, 23, 3, 5, 6, 3, 4, 29, 4, 31, 2, 6, 6, 6, 3, 37, 7, 7, 3, 41, 4, 43, 4, 4, 7, 47, 3, 7, 4, 8, 4, 53, 3, 8, 3, 8, 8, 59, 3, 61, 8, 4, 2, 9, 5, 67, 5, 9, 5, 71, 3, 73, 9, 5, 5, 9, 5, 79, 3, 3, 10, 83, 4, 10, 10, 10, 4, 89, 4, 10, 5, 10
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 13 2003

Keywords

Crossrefs

Programs

  • Mathematica
    A079870[n_] := If [n == 1, 1, Ceiling[n^(1/PrimeOmega[n])]];
    Array[A079870, 100] (* Paolo Xausa, Oct 28 2024 *)
  • PARI
    a(n) = if (n==1, 1, ceil(n^(1/bigomega(n)))); \\ Michel Marcus, May 31 2016

Formula

A079871(n) = a(n)^A001222(n).
a(n) >= A079868(n); A020639(n) <= a(n) <= A006530(n);
a(m) = A079868(m) iff m is a prime power (A000961).

A079867 a(1)=1 and for n>1: floor(n^(1/Omega(n)))^Omega(n), where Omega(n) is the total number of prime factors of n (A001222).

Original entry on oeis.org

1, 2, 3, 4, 5, 4, 7, 8, 9, 9, 11, 8, 13, 9, 9, 16, 17, 8, 19, 8, 16, 16, 23, 16, 25, 25, 27, 27, 29, 27, 31, 32, 25, 25, 25, 16, 37, 36, 36, 16, 41, 27, 43, 27, 27, 36, 47, 32, 49, 27, 49, 27, 53, 16, 49, 16, 49, 49, 59, 16, 61, 49, 27, 64, 64, 64, 67, 64, 64, 64, 71, 32, 73, 64
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 13 2003

Keywords

Comments

a(n)<=A079869(n); A020639(n)<=a(n)<=A006530(n);
a(m)=m=A079869(m)=A079871(m) iff m is a prime power (A000961).

Crossrefs

a(n)=A079866(n)^A001222(n), cf. A068794, A068795.

Programs

  • Mathematica
    Join[{1},Table[Floor[n^(1/PrimeOmega[n])]^PrimeOmega[n],{n,2,80}]] (* Harvey P. Dale, May 19 2018 *)

A079868 a(1)=1 and for n>1: round(n^(1/Omega(n))), where Omega(n) is the total number of prime factors of n (A001222).

Original entry on oeis.org

1, 2, 3, 2, 5, 2, 7, 2, 3, 3, 11, 2, 13, 4, 4, 2, 17, 3, 19, 3, 5, 5, 23, 2, 5, 5, 3, 3, 29, 3, 31, 2, 6, 6, 6, 2, 37, 6, 6, 3, 41, 3, 43, 4, 4, 7, 47, 2, 7, 4, 7, 4, 53, 3, 7, 3, 8, 8, 59, 3, 61, 8, 4, 2, 8, 4, 67, 4, 8, 4, 71, 2, 73, 9, 4, 4, 9, 4, 79, 2, 3, 9, 83, 3, 9, 9, 9, 3, 89, 3, 10, 5, 10, 10
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 13 2003

Keywords

Comments

A079866(n)<=a(n)<=A079870(n); A020639(n)<=a(n)<=A006530(n);
a(m)=A079866(m)=A079870(m) iff m is a prime power (A000961).

Crossrefs

Cf. A079869(n)=a(n)^A001222(n), A079881.

Programs

  • Mathematica
    Join[{1},Table[Floor[n^(1/PrimeOmega[n])+1/2],{n,2,100}]] (* Harvey P. Dale, Aug 11 2012 *)

A079872 a(1)=0, a(n) = signum(round(n^(1/Omega(n)))^Omega(n) - n), where Omega(n) is the total number of prime factors of n (A001222).

Original entry on oeis.org

0, 0, 0, 0, 0, -1, 0, 0, 0, -1, 0, -1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, -1, 0, -1, 0, -1, 0, -1, 0, 0, 1, 1, 1, -1, 0, -1, -1, 1, 0, -1, 0, 1, 1, 1, 0, -1, 0, 1, -1, 1, 0, 1, -1, 1, 1, 1, 0, 1, 0, 1, 1, 0, -1, -1, 0, -1, -1, -1, 0, -1, 0, 1, -1, -1, 1, -1, 0, -1, 0, -1, 0, -1, -1, -1, -1, -1, 0, -1, 1, 1, 1, 1, 1, -1
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 13 2003

Keywords

Comments

a(m) = 0 iff m is a prime power (A000961).

Crossrefs

Programs

  • Mathematica
    A079872[n_] := If[n == 1, 0, Sign[Round[n^(1/#)]^# - n] & [PrimeOmega[n]]];
    Array[A079872, 100] (* Paolo Xausa, Sep 02 2025 *)

Formula

a(n) = A057427(A079869(n) - n).
Showing 1-5 of 5 results.