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.

A095005 Number of odious primes (A027697) in range ]2^n,2^(n+1)].

Original entry on oeis.org

0, 1, 2, 2, 5, 8, 19, 20, 48, 75, 160, 242, 505, 835, 1761, 2799, 5890, 10250, 20921, 36872, 74316, 134816, 267749, 492286, 977207, 1823657, 3598657, 6779899, 13336543, 25358424, 49763462, 95140695, 186504600, 358630024, 702300885, 1356118149, 2654709953, 5142968571
Offset: 1

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Author

Antti Karttunen and Labos Elemer, Jun 01 2004

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Count[Prime@ Range[PrimePi[2^n] + 1, PrimePi[2^(n + 1) - 1]], k_ /; OddQ@ First@ DigitCount[k, 2]], {n, 24}] (* Michael De Vlieger, Feb 25 2017 *)
  • PARI
    a(n) = #select(x->((hammingweight(x)%2)==1),primes([2^n+1,2^(n+1)])); \\ Michel Marcus, Feb 26 2017

Formula

a(n) = A036378(n) - A095006(n).

Extensions

a(34)-a(38) from Amiram Eldar, Jun 20 2024