A065774 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.

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

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 400 terms from Harry J. Smith)

Mathematica

Select[Range[2, 10^5], Times @@ IntegerDigits @ # == Plus @@ Times @@@ FactorInteger @ # &] (* Giovanni Resta, Apr 23 2017 *)

Prog

(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

Crossrefs

Cf. A067173, A001414, A007954.

Sequence in context: A101012 A373961 A048659 * A281233 A048459 A203615

Adjacent sequences: A065771 A065772 A065773 * A065775 A065776 A065777

Keyword

base,easy,nonn

Author

Jason Earls, Dec 04 2001

Extensions

Offset changed from 0 to 1 by Harry J. Smith, Oct 30 2009

Status

approved