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.

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A337013 Prime numbers arising in A336817.

Original entry on oeis.org

3, 7, 3, 5, 7, 3, 13, 2, 3, 2, 5, 2, 3, 2, 31, 2, 3, 2, 7, 2, 3, 2, 13, 2, 3, 2, 5, 2, 3, 2, 61, 2, 3, 2, 5, 2, 3, 2, 13, 2, 3, 2, 5, 2, 3, 2, 31, 2, 3, 2, 7, 2, 3, 2, 13, 2, 3, 2, 5, 2, 3, 2, 127, 2, 3, 2, 7, 2, 3, 2, 13, 2, 3, 2, 5, 2, 3, 2, 31, 2, 3, 2, 7
Offset: 1

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Author

Rémy Sigrist, Nov 21 2020

Keywords

Comments

This sequence contains large runs of consecutive terms that are repeated later on.

Examples

			a(7) = A336817(7) XOR A336817(8) = 7 XOR 10 = 13.
		

Crossrefs

Programs

  • PARI
    s=0; v=1; for (n=1, 83, s+=2^v; for (w=1, oo, if (!bittest(s, w) && isprime(p=bitxor(v, w)), print1 (p ", "); v=w; break)))

Formula

a(n) = A336817(n) XOR A336817(n+1) (where XOR denotes the bitwise XOR operator).

A352722 Lexicographically earliest sequence of distinct positive integers such that a(1) = 2 and for any n > 0, a(n) AND a(n+1) is prime (where AND denotes the bitwise AND operator).

Original entry on oeis.org

2, 3, 6, 10, 7, 5, 13, 15, 11, 18, 14, 19, 17, 21, 25, 23, 27, 34, 22, 35, 26, 38, 66, 30, 67, 31, 29, 37, 39, 45, 41, 43, 47, 53, 55, 61, 63, 59, 70, 42, 71, 50, 74, 51, 75, 54, 130, 46, 82, 131, 58, 134, 83, 49, 81, 57, 85, 133, 69, 135, 77, 73, 79, 87, 91
Offset: 1

Views

Author

Rémy Sigrist, Mar 30 2022

Keywords

Comments

See A352723 for the corresponding prime numbers.
Terms of A102211 clearly do not occur in this sequence. Is this a permutation of the complement of A102211 in the positive integers? - Peter Munn, Sep 02 2022

Examples

			The first terms, alongside the corresponding prime numbers, are:
  n   a(n)  a(n) AND a(n+1)
  --  ----  ---------------
   1     2                2
   2     3                2
   3     6                2
   4    10                2
   5     7                5
   6     5                5
   7    13               13
   8    15               11
   9    11                2
  10    18                2
		

Crossrefs

Cf. A102211, A308334 (OR variant), A336817 (XOR variant), A352723.

Programs

  • PARI
    s=0; v=2; for (n=1, 65, print1 (v", "); s+=2^v; for (w=1, oo, if (!bittest(s, w) && isprime(bitand(v,w)), v=w; break)))
Showing 1-2 of 2 results.