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 1-1 of 1 results.

A178595 Natural numbers sorted by the sum of square roots of prime factors.

Original entry on oeis.org

1, 2, 3, 5, 7, 4, 6, 11, 9, 13, 10, 15, 14, 17, 8, 19, 21, 25, 12, 22, 23, 18, 35, 26, 33, 20, 27, 49, 39, 30, 29, 28, 34, 55, 31, 16, 45, 38, 42, 65, 51, 50, 77, 24, 37, 57, 63, 44, 75, 46, 91, 36, 70, 85, 41, 52, 66, 40, 69, 43, 95, 54, 105, 121, 98, 125, 78, 119, 99, 60, 58
Offset: 1

Views

Author

Joonas Pohjonen, May 30 2010

Keywords

Comments

Prime factors counted with multiplicity. - Harvey P. Dale, May 20 2023

Crossrefs

Similarly defined sequences: A064364, A168521.

Programs

  • Mathematica
    SortBy[Table[{n,Total[N[Sqrt[Flatten[Table[#[[1]],#[[2]]]&/@FactorInteger[n]]]]]},{n,150}],Last][[;;,1]] (* Harvey P. Dale, May 20 2023 *)

Formula

For n >= 1, Sum_{k=1..A001222(a(n))} sqrt(A027746(a(n),k)) < Sum_{k=1..A001222(a(n+1))} sqrt(A027746(a(n+1),k)). - Peter Munn, Aug 17 2022
Showing 1-1 of 1 results.