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A285494 Numbers k such that digit sum of k = number of distinct prime factors of k. 4
20, 30, 102, 120, 200, 300, 1002, 1200, 2000, 2001, 2002, 3000, 3010, 10001, 10002, 10011, 10030, 10120, 11001, 11020, 11110, 12000, 20000, 20001, 21010, 30000, 30030, 30100, 100001, 100030, 100101, 100130, 100210, 100300, 101001, 101101, 101200, 102102, 110001, 110200 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..10000

MATHEMATICA

Select[Range[2, 10000], Total[IntegerDigits[#]]==Length[FactorInteger[#]]&] (* or *)

nd = 10; s = 1; Sort@ Flatten@ Reap[ While[ Times @@ Prime[ Range@ s] < 10^nd, pa = IntegerPartitions[s, {nd}, Range[0, 9]]; Do[Sow@ Select[ FromDigits /@ Permutations[p], PrimeNu[#] == s &], {p, pa}]; s++]][[2, 1]] (* terms < 10^10, Giovanni Resta, Apr 21 2017 *)

PROG

(PARI) isok(n) = sumdigits(n) == omega(n); \\ Michel Marcus, Apr 20 2017

CROSSREFS

Cf. A001221, A007953, A057531, A057532, A050689, A070274, A070275, A063737, A067077.

Sequence in context: A008444 A268984 A066214 * A120210 A181639 A166631

Adjacent sequences:  A285491 A285492 A285493 * A285495 A285496 A285497

KEYWORD

nonn,base

AUTHOR

Jonathan Frech, Apr 19 2017

EXTENSIONS

More terms from Michel Marcus, Apr 20 2017

STATUS

approved

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Last modified June 25 19:53 EDT 2017. Contains 288729 sequences.