A067183 Product of the prime factors of n equals the product of the digits of n.
1, 2, 3, 5, 6, 7, 135, 175, 735, 1176, 1715, 131712
Offset: 1
Examples
The prime factors of 1176 are 2,3,7 which have product = 42, the product of the digits of 1176, so 1176 is a term of the sequence.
Programs
-
Mathematica
Do[ If[ Apply[ Times, Transpose[ FactorInteger[n]] [[1]] ] == Apply[ Times, IntegerDigits[n]], Print[n]], {n, 2, 2*10^7} ] Select[Range[2,1000000],Times@@Transpose[FactorInteger[#]][[1]] == Times@@ IntegerDigits[#]&] (* Harvey P. Dale, Mar 19 2012 *) -
PARI
is(n) = {if(n == 1, return(1)); my(f = factor(n, 7), d = digits(n)); if(f[#f~, 1] > 7, return(0)); vecprod(f[,1]) == vecprod(d)} \\ David A. Corneth, Sep 14 2022
Extensions
Edited and extended by Robert G. Wilson v, Feb 19 2002
a(1)=1 inserted by Alois P. Heinz, Sep 14 2022
Comments