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.

A126975 Primes p with property that, if q is the next prime, then the sum of the prime factors of p+q, taken with multiplicity, is a prime.

Original entry on oeis.org

2, 5, 23, 43, 83, 97, 103, 131, 149, 157, 179, 191, 193, 229, 251, 293, 337, 383, 397, 401, 431, 443, 463, 541, 569, 601, 643, 709, 739, 857, 859, 863, 887, 907, 911, 967, 971, 983, 1019, 1039, 1069, 1091, 1093, 1223, 1229, 1249, 1279, 1283, 1321, 1373
Offset: 1

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Author

J. M. Bergot, Mar 20 2007

Keywords

Examples

			97 is a member: 97 + 101 = 198. Its factors with multiplicity are 2*3*3*11 and their sum is 2+3+3+11=19, which is a prime.
		

Crossrefs

Cf. A086711.

Programs

  • Magma
    [ p: p in PrimesUpTo(1400) | IsPrime(&+[ k[1]*k[2]: k in Factorization(p+NextPrime(p)) ] ) ]; /* Klaus Brockhaus, Mar 25 2007 */
    
  • Mathematica
    sopfr[n_] := Plus @@ Times @@@ FactorInteger[n];Prime@Select[Range[240], PrimeQ[sopfr[Prime[ # ] + Prime[ # + 1]]] &] (* Ray Chandler, Mar 25 2007 *)
  • PARI
    {m=1400; p=2; while(p
    				

Extensions

Corrected and extended by Ray Chandler and Klaus Brockhaus, Mar 25 2007