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 A325957 Sophie Germain primes equal to the sum of the first k Sophie Germain primes for some k. 1
 2, 5, 39233, 50969, 5402909, 6899969, 7722119, 10490933, 24296873, 46322183, 95837639, 117933353, 122693729, 132514703, 181862003, 303953873, 762321281, 929234279, 1044329843, 1150361501, 1335588539, 1353590321, 1662019811, 2048876033, 2176318433, 2250982931 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The sum of first 268 terms of this sequence is also a Sophie Germain prime. 2 + 5 + 39233 + ... + 1187321288921 = 91753770231881. LINKS Metin Sariyar, Table of n, a(n) for n = 1..999 FORMULA Equals A005384 Intersection A066819. EXAMPLE 39233 is a term because sum of the first 56 Sophie Germain primes 2 + 3 + 5 + ... + 1811 = 39233 is prime and 39233*2+1 = 78467 is prime. MATHEMATICA lst={}; s=0; Do[If[PrimeQ[n]&&PrimeQ[2*n+1], s=s+n; If[PrimeQ[s]&&PrimeQ[s*2+1], AppendTo[lst, s]]], {n, 1, 1000000}]; lst PROG (PARI) issg(p) = isprime(2*p+1); lista(nn) = {my(s=0); forprime(p=2, nn, if (issg(p), s + = p; if (isprime(s) && issg(s), print1(s, ", "); ); ); ); } \\ Michel Marcus, Sep 11 2019 CROSSREFS Cf. A000040, A005384, A005385, A013918, A066819, A172037. Sequence in context: A057678 A090071 A319898 * A247148 A139062 A241861 Adjacent sequences: A325954 A325955 A325956 * A325958 A325959 A325960 KEYWORD nonn AUTHOR Metin Sariyar, Sep 10 2019 STATUS approved

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Last modified April 15 20:47 EDT 2024. Contains 371696 sequences. (Running on oeis4.)