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A065774
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Numbers k such that the product of the digits of k is equal to the sum of the prime factors of k, counted with multiplicity.
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2
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2, 3, 4, 5, 7, 18, 25, 154, 329, 418, 442, 532, 1519, 1826, 2354, 2472, 2781, 3383, 4343, 4712, 5282, 5561, 6171, 6623, 7922, 9331, 9911, 11248, 12328, 12773, 13125, 14193, 15194, 16512, 17267, 19852, 21479, 24516, 26522, 31816, 32661, 36512
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Select[Range[2, 10^5], Times @@ IntegerDigits @ # == Plus @@ Times @@@ FactorInteger @ # &] (* Giovanni Resta, Apr 23 2017 *)
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PROG
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(PARI) ProdD(x)= { local(p=1); while (x>9 && p>0, p*=(x-10*(x\10)); x\=10); return(p*x) }
sopfr(n)= { local(f, s=0); f=factor(n); for(i=1, matsize(f)[1], s+=f[i, 1]*f[i, 2]); return(s) }
{ n=0; for (m=1, 10^9, if (ProdD(m) == sopfr(m), write("b065774.txt", n++, " ", m); if (n==400, return)) ) } \\ Harry J. Smith, Oct 30 2009
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CROSSREFS
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KEYWORD
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base,easy,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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