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A176544
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Primes of the form semiprime(k)/sum of digits of semiprime(k).
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1
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7, 37, 19, 67, 19, 19, 37, 37, 73, 37, 73, 337, 367, 163, 73, 109, 127, 73, 109, 163, 127, 181, 163, 433, 181, 163, 199, 181, 271, 163, 199, 199, 271, 271, 397, 307, 307, 487, 379, 541, 433, 577, 397, 271, 631, 433, 379, 487, 919, 1459, 541, 937, 811, 631, 991
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OFFSET
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1,1
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LINKS
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FORMULA
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EXAMPLE
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7 is a term because 7 = 21/(2+1);
37 is a term because 37 = 111/(1+1+1).
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MAPLE
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A175013 := proc(n) A007953(A001358(n)) ; end proc: A007953 := proc(n) add(d, d=convert(n, base, 10)) ; end proc: for n from 1 to 4000 do r := A001358(n)/A175013(n) ; if type(r, 'integer') then if isprime(r) then printf("%d, ", r) ; end if; end if; end do: # R. J. Mathar, Apr 26 2010
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MATHEMATICA
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Select[#/Total[IntegerDigits[#]]&/@Select[Range[30000], PrimeOmega[#]==2&], PrimeQ] (* Harvey P. Dale, Aug 10 2023 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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