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.

A144213 Primes with a prime number of 0's in their binary representations.

Original entry on oeis.org

17, 19, 37, 41, 43, 53, 71, 79, 83, 89, 101, 103, 107, 109, 113, 131, 137, 151, 157, 167, 173, 179, 181, 193, 199, 211, 227, 229, 233, 241, 257, 263, 269, 277, 281, 293, 311, 317, 337, 347, 349, 353, 359, 367, 373, 379, 389, 401, 431, 439, 443, 449, 461, 463
Offset: 1

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Author

Leroy Quet, Sep 14 2008

Keywords

Examples

			41, a prime, in binary is 101001. This has three 0's and 3 is prime, so 41 is in the sequence.
		

Crossrefs

Cf. A081092, A144214. Intersection of A000040 and A144754.

Programs

  • Maple
    A080791 := proc(n) local i,dgs ; dgs := convert(n,base,2) ; nops(dgs)-add(i,i=dgs) ; end: isA144213 := proc(n) local no0 ; no0 := A080791(n) ; if isprime(n) and isprime(no0) then true ; else false; fi; end: for n from 1 to 1200 do if isA144213(n) then printf("%d,",n) ; fi; od: # R. J. Mathar, Sep 17 2008
    # second Maple program:
    q:= n-> isprime(n) and isprime(add(1-i, i=Bits[Split](n))):
    select(q, [$1..500])[];  # Alois P. Heinz, Dec 27 2023
  • Mathematica
    nmax = 100;
    Select[Prime[Range[nmax]],
    PrimeQ[Total@Mod[1 + IntegerDigits[#, 2], 2]] &] (* Andres Cicuttin, Jul 08 2020 *)
    Select[Prime[Range[100]],PrimeQ[DigitCount[#,2,0]]&] (* Harvey P. Dale, Feb 03 2021 *)
  • Python
    from sympy import isprime
    def ok(n): return isprime(n.bit_length()-n.bit_count()) and isprime(n)
    print([k for k in range(464) if ok(k)]) # Michael S. Branicky, Dec 27 2023

Extensions

More terms from R. J. Mathar, Sep 17 2008