OFFSET
1,1
COMMENTS
This sequence is finite with its largest term < 10^70. - Stefan Steinerberger, Apr 24 2006
a(15) > 1.288 * 10^10 if it exists. - Kevin P. Thompson, Oct 19 2021
EXAMPLE
364 is in the sequence because the product of its digits is 3*6*4 = 72 and there are 72 prime numbers smaller than 364.
MATHEMATICA
Select[Range[50000], DigitCount[ # ][[10]] == 0 && Product[i^DigitCount[ # ][[i]], {i, 1, 9}] == PrimePi[ # - 1] &] (* Stefan Steinerberger, Apr 24 2006 *)
g[n_] := Product[IntegerDigits[n][[m]], {m, 1, Length[IntegerDigits[n]]}]; Do[If[g[n] == PrimePi[n], Print[n]], {n, 1, 10000000}] (* Mohammed Bouayoun (Mohammed.bouayoun(AT)sanef.com), Apr 24 2006 *)
PROG
(PARI) isok(m) = vecprod(digits(m)) == primepi(m); \\ Michel Marcus, Oct 23 2021
CROSSREFS
KEYWORD
nonn,base,fini,more
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), Apr 23 2006
EXTENSIONS
More terms from Zak Seidov, Stefan Steinerberger and Mohammed Bouayoun (Mohammed.bouayoun(AT)sanef.com), Apr 24 2006
STATUS
approved