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.

A371533 Numbers k such that A001227(2*k) = A001222(2*k).

Original entry on oeis.org

1, 3, 5, 7, 9, 11, 13, 17, 19, 23, 25, 27, 29, 30, 31, 37, 41, 42, 43, 47, 49, 53, 59, 61, 66, 67, 70, 71, 73, 78, 79, 81, 83, 89, 97, 101, 102, 103, 107, 109, 110, 113, 114, 121, 125, 127, 130, 131, 137, 138, 139, 149, 151, 154, 157, 163, 167, 169, 170, 173, 174, 179, 180, 181, 182, 186, 190, 191, 193, 197, 199
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Mar 26 2024

Keywords

Crossrefs

Programs

  • Magma
    [k: k in [1..200] | #Divisors(4*k)-#Divisors(2*k) eq
    (2*k eq 1 select 0 else &+[p[2]: p in Factorization(2*k)])];
  • Mathematica
    Select[Range[200], DivisorSigma[0, #/2^IntegerExponent[#, 2]] == PrimeOmega[2*#] &] (* Amiram Eldar, Mar 26 2024 *)