A366206 Numbers k such that the sum of the first k primes is the average of a twin prime pair.
57, 103, 123, 211, 213, 273, 347, 943, 1073, 1951, 2185, 2365, 2375, 2379, 2501, 2751, 2761, 2855, 3095, 3651, 3731, 3791, 3799, 4503, 4529, 4843, 5199, 5851, 5927, 5959, 6163, 7151, 7305, 7611, 8101, 8761, 9045, 9061, 9429, 9497, 9741, 9909, 10071, 10105, 10401
Offset: 1
Keywords
Links
- Paolo Xausa, Table of n, a(n) for n = 1..5000
Programs
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Mathematica
With[{upto=10^4},Flatten[Position[Accumulate[Prime[Range[upto]]],_?(PrimeQ[#-1]&&PrimeQ[#+1]&)]]] -
PARI
isok(k) = my(s=vecsum(primes(k))); isprime(s-1) && isprime(s+1); \\ Michel Marcus, Oct 04 2023