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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A245590 Primes p such that p^2 + 6 is a semiprime.

Original entry on oeis.org

2, 3, 7, 17, 23, 41, 47, 53, 59, 101, 149, 157, 173, 179, 193, 211, 229, 233, 239, 241, 251, 311, 347, 349, 353, 359, 373, 379, 383, 389, 409, 421, 439, 443, 457, 479, 499, 509, 521, 541, 571, 577, 599, 619, 641, 661, 691, 701, 719, 751, 761, 769, 809, 823, 829
Offset: 1

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Author

K. D. Bajpai, Jul 26 2014

Keywords

Examples

			7 is in the sequence because it is prime and 7^2 + 6 = 55 = 5 * 11, which is semiprime.
23 is in the sequence because it is prime and 23^2 + 6 = 535 = 5 * 107, which is semiprime.
		

Crossrefs

Cf. A109953 (primes p: p^2 + 2 is semiprime).
Cf. A243365 (primes p: p^2 + 6 and p^2 - 6 are semiprimes).

Programs

  • Maple
    with(numtheory):A245590:=n->`if`(isprime(n) and bigomega(n^2+6)=2, n, NULL): seq(A245590 (n), n=1..1500);
  • Mathematica
    Select[Prime[Range[200]], PrimeOmega[#^2 + 6] == 2 &]
  • PARI
    forprime(p=1,10^4,if(bigomega(p^2+6)==2,print1(p,", "))) \\ Derek Orr, Aug 03 2014
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