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1, 1, 11, 1, 79, 26, 339, 34, 5297, 62, 69071, 1165, 11723, 9844, 471181, 2625, 8960447, 73244, 8231001, 243757, 1031626241, 151100, 4178462515, 2651758, 10396147563, 11843614, 64166447971, 362476, 1989542332021, 97275764008, 1830230212061, 57286319768
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OFFSET
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3,3
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COMMENTS
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A182972(n) and A182973(n) provide an enumeration of positive rationals < 1 arranged by increasing sum of numerator and denominator then by increasing numerator;
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LINKS
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EXAMPLE
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. ----+----------------------------------+---------+---------+--------
. 3 | 1/2 | 1 | 2 | 0
. 4 | 1/3 | 1 | 3 | 0
. 5 | 1/4, 2/3 | 11 | 12 | 0
. 6 | 1/5 | 1 | 5 | 0
. 7 | 1/6, 2/5, 3/4 | 79 | 60 | 1
. 8 | 1/7, 3/5 | 26 | 35 | 0
. 9 | 1/8, 2/7, 4/5 | 339 | 280 | 1
. 10 | 1/9, 3/7 | 34 | 63 | 0
. 11 | 1/10, 2/9, 3/8, 4/7, 5/6 | 5297 | 2520 | 2
. 12 | 1/11, 5/7 | 62 | 77 | 0
. 13 | 1/12, 2/11, 3/10, 4/9, 5/8, 6/7 | 69071 | 27720 | 2
. 14 | 1/13, 3/11, 5/9 | 1165 | 1287 | 0
. 15 | 1/14, 2/13, 4/11, 7/8 | 11723 | 8008 | 1
. 16 | 1/15, 3/13, 5/11, 7/9 | 9844 | 6435 | 1 .
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PROG
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(Haskell)
import Data.Ratio ((%), numerator)
a245677 n = numerator $ sum
[num % den | num <- [1 .. div n 2], let den = n - num, gcd num den == 1]
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CROSSREFS
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KEYWORD
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nonn,frac
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AUTHOR
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STATUS
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approved
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