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1, 2, 4, 9, 12, 21, 24, 30, 42, 45, 57, 60, 75, 84, 90, 105, 135, 150, 165, 195, 210, 255, 315, 330, 390, 420, 525, 630, 735, 825, 840, 945, 1050, 1155, 1365, 1575, 1680, 1785, 1995, 2100, 2145, 2205, 2310, 2625, 2730, 3045, 3255, 3465, 3990
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OFFSET
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1,2
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LINKS
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MAPLE
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A008578 := proc(n) RETURN( n=1 or isprime(n) ) ; end : A154804 := proc(n) local a, d; a := 0 ; for d from 1 to n-1 do if A008578(n-d) and A008578(n+d) then a := a+1; fi; od: a ; end: a804 := [seq(A154804(n), n=1..4000)] ; r := RECORDS(a804)[2] ; # R. J. Mathar, Mar 14 2009
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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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