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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
OFFSET
1,1
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
Sequence in context: A088147 A302446 A109579 * A168269 A326936 A336416
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Jun 29 2005
STATUS
approved