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Search: id:A118500
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| A118500 |
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A variation on Flavius's sieves (A000960, A099207): Start with Chen primes; at the k-th sieving step, remove every (k+1)-st term of the sequence remaining after the (k-1)-st sieving step; iterate. |
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1
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| 2, 5, 17, 41, 83, 137, 233, 317, 467, 617, 761, 941, 1259, 1427, 1913, 2281, 2531, 2957, 3511, 3797, 4447, 5153, 5351, 6481, 6863, 7669, 8581, 9533, 10259, 11497, 12569, 13441, 14081, 15737, 16187, 17657, 19541, 19991, 21587, 23017, 24317
(list; graph; listen)
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OFFSET
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0,1
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EXAMPLE
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Start with
2 3 5 7 11 13 17 19 23 29 31 37 41 47 53 59 67 71 83 89 101 107 109 113 127 131 ... and delete every second term, giving
2 5 11 17 23 31 41 53 67 83 101 109 127 ... and delete every 3rd term, giving
2 5 17 23 41 53 83 101 127 ... and delete every 4th term, giving
.... Continue for ever, and what's left is the sequence.
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MAPLE
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ts_chen:= proc(n) local i, ans; ans:=[ ]: for i from 1 to n do if ( isprime(i) = 'true') then if ( isprime(i+2) = 'true' or numtheory[bigomega](i+2) = 2) then ans:=[ op(ans), i ] fi fi od: return ans end: S[1]:=convert(ts_chen(25000), set): for n from 2 to 2500 do S[n]:=S[n-1] minus {seq(S[n-1][n*i], i=1..nops(S[n-1])/n)} od: convert(S[2100], list);
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CROSSREFS
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Cf. A000960, A099207, A109611.
Sequence in context: A114300 A099207 A122566 this_sequence A080898 A013918 A007351
Adjacent sequences: A118497 A118498 A118499 this_sequence A118501 A118502 A118503
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KEYWORD
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nonn
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AUTHOR
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Jani Melik (jani_melik(AT)hotmail.com), May 05 2006
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