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1, 6, 29, 41, 53, 59, 65, 89, 97, 126, 137, 148, 163, 179, 191, 192, 193, 223, 233, 239, 250, 252, 257, 269, 281, 307, 311, 330, 336, 359, 372, 389, 402, 419, 431, 457, 491, 504, 508, 521, 547, 557, 569, 598, 613, 641, 653, 659, 673, 683, 700, 719, 733, 739
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internal format)
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OFFSET
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1,2
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COMMENTS
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(Number of primes of the form n-2^k) = (number of primes of the form n-2^k+1).
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LINKS
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FORMULA
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EXAMPLE
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MAPLE
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A109925 := proc(n) a := 0 ; for k from 0 do p := n-2^k ; if p < 2 then return a; elif isprime(p) then a := a+1 ; end if; end do: end proc:
for n from 1 to 1500 do if isA175956(n) then printf("%d, ", n); end if; end do:
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PROG
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(Magma) a109925:=function(n); count:=0; e:=1; while e le n do if IsPrime(n-e) then count+:=1; end if; e*:=2; end while; return count; end function; S:=[]; a:=a109925(1); for n in [1..750] do b:=a109925(n+1); if a eq b then Append(~S, n); end if; a:=b; end for; S; // Klaus Brockhaus, Oct 30 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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