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A161975
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Sum_{x=sum of prime factors of n-th composite..n-th composite} x.
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2
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4, 11, 21, 30, 34, 57, 69, 92, 108, 143, 174, 186, 175, 264, 280, 246, 342, 351, 420, 483, 470, 424, 564, 621, 531, 660, 765, 837, 885, 980, 781, 1121, 1134, 1209, 1136, 1242, 1430, 1420, 1518, 1422, 1246, 1764, 1425, 1938, 2014, 1992, 2091, 2136, 2090, 2394
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OFFSET
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1,1
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LINKS
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EXAMPLE
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4(=4), 11(=(2+3)+6), 22(=(2+2+2)+7+8), 30(=(3+3)+7+9), 34(=(2+5)+8+9+10), etc.
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MAPLE
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PROG
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(PARI) a(n)=my(c=n+n\log(n+1), f); for(i=0, n-c+primepi(c), if(isprime(c++), i--)); f=factor(c); binomial(c+1, 2)-binomial(sum(i=1, #f[, 1], f[i, 1]*f[i, 2]), 2)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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a(3), a(12) and others corrected by R. J. Mathar, Aug 03 2009
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STATUS
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approved
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