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A176512
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Indices of products of 2 single (or isolated or non-twin) primes in the semiprimes.
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1
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1, 16, 25, 33, 35, 45, 52, 55, 58, 62, 76, 82, 84, 100, 104, 107, 111, 133, 137, 143, 155, 158, 162, 164, 174, 183, 188, 194, 198, 202, 214, 218, 222, 225, 229, 231, 234, 241, 243, 249, 257, 263, 265, 269, 274, 281, 287, 292, 294, 299, 301, 304, 319, 320, 321
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OFFSET
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1,2
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LINKS
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FORMULA
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MAPLE
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isA007510 := proc(n) isprime(n) and not isprime(n+2) and not isprime(n-2) ; simplify(%) ; end proc:
isA176312 := proc(n) for d in numtheory[divisors](n) do if isA007510(d) and isA007510(n/d) then return true; end if; end do: return false; end proc:
A176312 := proc(n) option remember; if n = 1 then 4; else for a from procname(n-1)+1 do if isA176312(a) then return a; end if; end do: end if; end proc:
A174956 := proc(p) option remember ; for n from 1 do if A001358(n) = p then return n; elif A001358(n) > p then return 0 ; end if; end do: end proc:
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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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