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4, 5, 5, 5, 7, 7, 9, 8, 6, 7, 9, 10, 13, 8, 7, 15, 6, 11, 10, 7, 14, 19, 12, 9, 21, 16, 10, 12, 15, 10, 25, 9, 9, 9, 20, 17, 8, 16, 12, 22, 31, 12, 33, 12, 8, 18, 16, 21, 26, 14, 10, 39, 10, 23, 18, 18, 11, 7, 43, 14, 22, 45, 32, 16, 12, 20, 27, 34, 49, 24, 10, 11, 16, 11, 22, 18, 15, 55
(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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EXAMPLE
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Let k(n) = n-th composite (A002808(n)). Then:
a(4)=5 because k(4) = 9 = 3^2 and 5=3+2;
a(9)=6 because k(9) = 16 = 2^4 and 6=2+4;
a(10)=7 because k(10) = 18 = 2*3^2 and 7=2+3+2.
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MAPLE
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A141276 := proc(n) local a, ifs, p, c ; if not isprime(n) then a := 0 ; ifs := ifactors(n)[2] ; for p in ifs do a := a + op(1, p) ; if op(2, p) > 1 then a := a+ op(2, p) ; fi; od: printf("%d, ", a) ; end if; return ; end: for n from 4 to 200 do A141276(n); end do; # R. J. Mathar, Apr 28 2010
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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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STATUS
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approved
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