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 A109580 Primes in A109579. 0

%I

%S 3,3,7,7,11,11,11,11,13,13,17,17,17,17,23,23,29,29,29,29,61,61,71,71,

%T 71,71,83,83,83,83,83,83,107,107,107,107,137,137,137,137,137,137,137,

%U 137,149,149,193,193,227,227,227,227,227,227,241,241,241,241,281,281,307

%N Primes in A109579.

%p with(numtheory): a:=proc(n) if isprime(sum((pi(k+1)-pi(k))*(ithprime(k+1)-ithprime(k)),k=1..n))=true then sum((pi(k+1)-pi(k))*(ithprime(k+1)-ithprime(k)),k=1..n) else fi end: seq(a(n),n=1..230);

%t an = Table[(PrimePi[n + 1] - PrimePi[n])*(Prime[n + 1] - Prime[n]), {n, 1, 400}] a[0] = 0; a[n_] := a[n] = a[n - 1] + an[[n]] aa = Flatten[Table[If[PrimeQ[a[n]] == True, a[n], {}], {n, 0, Length[an]}]]

%Y Cf. A001223, A010051.

%K nonn

%O 1,1

%A _Roger L. Bagula_, Jun 29 2005

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Last modified September 25 02:16 EDT 2021. Contains 347651 sequences. (Running on oeis4.)