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 1-4 of 4 results.

A296077 a(n) = 1 if 1 + A002322(n) is prime, 0 otherwise, where A002322 is Carmichael lambda.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Dec 05 2017

Keywords

Comments

Out of the first 65537 values, 39743 are 1's (indicating primes), and 25794 are 0's, indicating nonprimes.

Crossrefs

Characteristic function for A263028.
Cf. A002322, A010051, A263027, A263029 (positions of zeros), A296076, A296079.

Programs

  • Mathematica
    Table[If[PrimeQ[CarmichaelLambda[n]+1],1,0],{n,120}] (* Harvey P. Dale, Sep 23 2020 *)
  • PARI
    A296077(n) = isprime(1+lcm(znstar(n)[2]));

Formula

a(n) = A010051(A263027(n)) = A010051(1+A002322(n)).

A263028 Numbers n such that A002322(n) + 1 is a prime, where A002322 is Carmichael lambda.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 82, 83
Offset: 1

Views

Author

Vincenzo Librandi, Oct 12 2015

Keywords

Comments

Complement of A263029.

Crossrefs

Cf. A002322, A263027, A263029, A296077 (characteristic function).
Cf. also A039698.

Programs

  • Magma
    [1] cat [n: n in [2..100] | IsPrime(CarmichaelLambda(n)+1)];
    
  • Mathematica
    Select[Range[1, 100], PrimeQ[CarmichaelLambda[#] + 1] &]
  • PARI
    for(n=1, 1e3, if(isprime((1 + lcm(znstar(n)[2]))), print1(n", "))) \\ Altug Alkan, Oct 12 2015

Extensions

More terms from Antti Karttunen, Dec 05 2017

A263029 Numbers n such that A002322(n) + 1 is not a prime, where A002322 is Carmichael lambda.

Original entry on oeis.org

25, 32, 50, 55, 75, 81, 96, 100, 110, 115, 119, 121, 128, 150, 153, 160, 162, 165, 176, 187, 200, 203, 209, 215, 220, 221, 224, 230, 235, 238, 242, 245, 253, 256, 261, 275, 287, 288, 289, 295, 297, 299, 300, 306, 319, 323, 324, 330, 335, 343, 345, 355
Offset: 1

Views

Author

Vincenzo Librandi, Oct 12 2015

Keywords

Comments

Complement of A263028.

Crossrefs

Positions of zeros in A296077.
Cf. also A039689.

Programs

  • Magma
    [n: n in [2..400] | not IsPrime(CarmichaelLambda(n)+1)];
    
  • Mathematica
    Select[Range[1, 400], ! PrimeQ[CarmichaelLambda[#] + 1] &]
  • PARI
    for(n=1, 1e3, if(isprime((1 + lcm(znstar(n)[2]))) == 0, print1(n", "))) \\ Altug Alkan, Oct 12 2015

A296076 Least number with the same prime signature as 1 + A002322(n), where A002322 is Carmichael's lambda.

Original entry on oeis.org

2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 6, 2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 12, 2, 2, 2, 4, 2
Offset: 1

Views

Author

Antti Karttunen, Dec 05 2017

Keywords

Crossrefs

Cf. A002322, A046523, A263027, A263028 (positions of 2's), A296077, A296078.

Programs

Formula

a(n) = A046523(A263027(n)) = A046523(1+A002322(n)).
Showing 1-4 of 4 results.