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A065870
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n-th prime - n-th semiprime.
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2
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-2, -3, -4, -3, -3, -2, -4, -3, -2, 3, -2, 3, 6, 5, 8, 7, 10, 10, 12, 14, 15, 17, 18, 20, 23, 24, 21, 22, 23, 26, 36, 38, 43, 44, 43, 40, 42, 45, 48, 52, 57, 58, 62, 60, 63, 58, 69, 80, 82, 83, 78, 81, 82, 90, 91, 94, 92, 93, 94, 96, 96, 99, 106, 109, 110, 112, 125, 128, 134, 135, 138, 142, 149, 154, 158, 157, 154, 160, 154, 160
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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Prime_1 - semiprime_1 = 2 - 4 = -2, prime_2 - semiprime_2 = 3 - 6 = -3, prime_3 - semiprime_3 = 5 - 9 = -4, etc.
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MATHEMATICA
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nn=250; Module[{pr=Prime[Range[nn]], sp=Select[Range[nn], PrimeOmega[ #]==2&], len}, len=Min[nn, Length[sp]]; #[[1]]-#[[2]]&/@ Thread[ {Take[ pr, len], Take[sp, len]}]](* Harvey P. Dale, Aug 14 2013 *)
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PROG
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(PARI) m=0; for (n=4, 250, if (bigomega(n) == 2, m = m + 1; print1(prime(m) - n, ", ")))
(PARI) n=m=0; for (k=1, 10^9, if (bigomega(k) != 2, next); m = m + 1; write("b065870.txt", n++, " ", prime(m) - k); if (n==1000, return) ) \\ Harry J. Smith, Nov 02 2009
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CROSSREFS
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KEYWORD
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easy,sign
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AUTHOR
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Robert A. Stump (bee_ess107(AT)yahoo.com), Dec 07 2001
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EXTENSIONS
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STATUS
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approved
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