OFFSET
1,2
EXAMPLE
n=100: prime set={2,5}, 3 digits and 2 digits of prime factors, so 100 is here;
n=147: prime set={3,7}, 3 digits and 2 digits of prime factors, so 147 is here.
MATHEMATICA
ffi[x_] :=Flatten[FactorInteger[x]] lf[x_] :=Length[FactorInteger[x]] ba[x_] :=Table[Part[ffi[x], 2*j-1], {j, 1, lf[x]}] tdp[x_] :=Flatten[Table[IntegerDigits[Part[ba[x], j]], {j, 1, lf[x]}], 1] pl[x_] :=Length[tdp[x]] nl[x_] :=Length[IntegerDigits[x]] t1=Table[nl[w], {w, 1, 1000}]; t2=Table[pl[w], {w, 1, 1000}]; t2-t1 Flatten[Position[t2-t1, -1]]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Labos Elemer, Jun 21 2004
STATUS
approved