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A256468
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Number of primes between prime(n)^2 and prime(n)*prime(n+1).
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6
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1, 2, 2, 6, 4, 8, 5, 12, 22, 8, 27, 21, 11, 23, 38, 36, 16, 43, 31, 15, 52, 36, 52, 75, 45, 22, 42, 19, 48, 160, 47, 81, 22, 141, 26, 90, 89, 65, 102, 96, 40, 180, 40, 73, 38, 227, 227, 85, 44, 85, 129, 43, 216, 133, 140, 137, 45, 147, 105, 46, 260, 354, 115, 52, 108, 386, 165, 283, 64
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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Table[Abs@ Subtract[PrimePi[Prime[n]^2], PrimePi[Prime[n] Prime[n + 1]]], {n, 69}] (* Michael De Vlieger, Mar 30 2015 *)
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PROG
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(PARI)
allocatemem(234567890);
default(primelimit, 4294965247);
A256468(n) = (primepi(prime(n)*prime(n+1)) - primepi(prime(n)^2));
for(n=1, 6542, write("b256468.txt", n, " ", A256468(n)));
(Scheme) (define (A256468 n) (let* ((p (A000040 n)) (p2 (* p p))) (let loop ((s 0) (k (* p (A000040 (+ 1 n))))) (cond ((= k p2) s) (else (loop (+ s (if (prime? k) 1 0)) (- k 1)))))))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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