login
A366206
Numbers k such that the sum of the first k primes is the average of a twin prime pair.
2
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
1,1
MATHEMATICA
With[{upto=10^4}, Flatten[Position[Accumulate[Prime[Range[upto]]], _?(PrimeQ[#-1]&&PrimeQ[#+1]&)]]]
PROG
(PARI) isok(k) = my(s=vecsum(primes(k))); isprime(s-1) && isprime(s+1); \\ Michel Marcus, Oct 04 2023
CROSSREFS
Cf. A007504, A014574, A366205 (corresponding sums).
Sequence in context: A147468 A147036 A147044 * A237663 A039535 A037990
KEYWORD
nonn
AUTHOR
Paolo Xausa, Oct 04 2023
STATUS
approved