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 A109580 Primes in A109579. 0
 3, 3, 7, 7, 11, 11, 11, 11, 13, 13, 17, 17, 17, 17, 23, 23, 29, 29, 29, 29, 61, 61, 71, 71, 71, 71, 83, 83, 83, 83, 83, 83, 107, 107, 107, 107, 137, 137, 137, 137, 137, 137, 137, 137, 149, 149, 193, 193, 227, 227, 227, 227, 227, 227, 241, 241, 241, 241, 281, 281, 307 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS MAPLE 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); MATHEMATICA 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]}]] CROSSREFS Cf. A001223, A010051. Sequence in context: A088147 A302446 A109579 * A168269 A326936 A336416 Adjacent sequences:  A109577 A109578 A109579 * A109581 A109582 A109583 KEYWORD nonn AUTHOR Roger L. Bagula, Jun 29 2005 STATUS approved

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Last modified July 25 02:57 EDT 2021. Contains 346282 sequences. (Running on oeis4.)