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.

A374613 Prime numbers p with the property that neither of 2*(p+next prime to p)+/-1 is prime.

Original entry on oeis.org

29, 71, 73, 79, 83, 127, 131, 137, 167, 173, 193, 197, 211, 223, 229, 233, 239, 251, 269, 331, 347, 349, 373, 419, 421, 431, 433, 439, 457, 467, 487, 503, 509, 541, 563, 577, 587, 619, 641, 647, 653, 659, 661, 691, 719, 727, 733, 743, 751, 797, 809, 811, 821, 829, 839, 853, 859, 863, 887
Offset: 1

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Author

Marcin Barylski, Jul 14 2024

Keywords

Comments

Conjecture: this sequence is infinite.

Examples

			2 is not a term because 2*(2+3)+1=11 is a prime.
5 is not a term because 2*(5+7)-1=23 is a prime.
29 is a term because neither 2(29+31)+1 nor 2(29+31)-1 is a prime.
		

Programs

  • Mathematica
    Prime[Select[Range[155], !PrimeQ[2(Prime[#]+Prime[#+1])-1] && !PrimeQ[2(Prime[#]+Prime[#+1])+1]&]] (* Stefano Spezia, Jul 15 2024 *)