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A066307 Nonprimes such that sum of digits equals product of digits. 6
1, 4, 6, 8, 9, 22, 123, 132, 213, 231, 312, 321, 1124, 1142, 1214, 1241, 1412, 1421, 2114, 4112, 4121, 11125, 11133, 11152, 11215, 11222, 11313, 11331, 11512, 11521, 12115, 12122, 12151, 12212, 12221, 13113, 13131, 13311, 15112, 15211, 21115 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Chai Wah Wu, Table of n, a(n) for n = 1..10000 (n = 1..516 from Harry J. Smith)

EXAMPLE

321 = 3*107, 3 + 2 + 1 = 6 = 3*2*1.

MATHEMATICA

sdpdQ[n_]:=Module[{idn=IntegerDigits[n]}, Total[idn]==Times@@idn]; Module[ {upto=25000, cs}, cs=Complement[Range[upto], Prime[Range[PrimePi[upto]]]]; Select[cs, sdpdQ]] (* Harvey P. Dale, Oct 14 2014 *)

PROG

(PARI) SumD(x)= { local(s=0); while (x>9, s+=x%10; x\=10); return(s + x) } ProdD(x)= { local(p=1); while (x>9 && p>0, p*=x%10; x\=10); return(p*x) } { n=0; for (m=1, 10^9, if (isprime(m), next); if (SumD(m)==ProdD(m), write("b066307.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Feb 09 2010

CROSSREFS

Composites and 1 from A034710.

Cf. A034710, A066306.

Sequence in context: A078337 A046351 A161732 * A287198 A099071 A156673

Adjacent sequences:  A066304 A066305 A066306 * A066308 A066309 A066310

KEYWORD

base,nonn

AUTHOR

Labos Elemer, Dec 13 2001

STATUS

approved

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Last modified May 25 17:53 EDT 2020. Contains 334595 sequences. (Running on oeis4.)