OFFSET
1,2
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..10000 (first 1000 terms from Harry J. Smith)
EXAMPLE
24 is a term as there are 8 divisors of 24 = 2*4.
MATHEMATICA
f[n_] := Block[ {a = Sort[ IntegerDigits[n]] }, While[ First[a] == 0, a = Drop[a, 1]]; Return[ Apply[ Times, a]]]; Select[ Range[10^4], f[ # ] == Length[ Divisors[ # ]] & ]
pndQ[n_]:=Times@@Select[IntegerDigits[n], #!=0&]==DivisorSigma[0, n]; Select[Range[2000], pndQ] (* Harvey P. Dale, Oct 25 2016 *)
PROG
(PARI) ProdNzD(x)= { local(d, p=1); while (x>9, d=x%10; if (d, p*=d); x\=10); return(p*x) } { n=0; for (m=1, 10^10, if (ProdNzD(m) == numdiv(m), write("b066613.txt", n++, " ", m); if (n==1000, return)) ) } \\ Harry J. Smith, Mar 12 2010
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Dec 24 2001
EXTENSIONS
Corrected and extended by Jason Earls and Robert G. Wilson v, Dec 26 2001
STATUS
approved