A114522 Numbers n such that sum of distinct prime divisors of n is prime.
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 16, 17, 18, 19, 20, 22, 23, 24, 25, 27, 29, 31, 32, 34, 36, 37, 40, 41, 43, 44, 47, 48, 49, 50, 53, 54, 58, 59, 61, 64, 67, 68, 71, 72, 73, 79, 80, 81, 82, 83, 88, 89, 96, 97, 100, 101, 103, 107, 108, 109, 113, 116, 118, 121, 125, 127
Offset: 1
Keywords
Examples
24 = 2^3 * 3 and 2 + 3 = 5, which is prime. So 24 is included.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
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Magma
[k:k in [2..150]| IsPrime(&+PrimeDivisors(k))]; // Marius A. Burtea, Oct 06 2019
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Mathematica
f[n_] := Plus @@ First /@ FactorInteger[n]; Select[Range[130], PrimeQ[f[ # ]] &] (* Ray Chandler, Dec 07 2005 *) Select[Range@127, PrimeQ[Plus @@ First /@ FactorInteger@# ] &] (* Robert G. Wilson v, Dec 07 2005 *)
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PARI
for(n=1, 200, v=factor(n); s=0; for(i=1,matsize(v)[1],s+=v[i,1]); if(isprime(s), print1(n, ", "))) \\ Lambert Herrgesell (zero815(AT)googlemail.com), Dec 07 2005
Extensions
Extended by Robert G. Wilson v, Ray Chandler and Lambert Herrgesell (zero815(AT)googlemail.com), Dec 07 2005
Comments