A095410 Numbers n such that total number of decimal digits of all distinct prime factors of n equals the number of digits of n.

2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 23, 24, 28, 29, 31, 35, 36, 37, 40, 41, 43, 45, 47, 48, 50, 53, 54, 56, 59, 61, 63, 67, 71, 72, 73, 75, 79, 80, 83, 89, 96, 97, 98, 101, 103, 104, 105, 106, 107, 109, 111, 113, 115, 116, 117, 118, 119, 120, 122

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Formula

Solutions to A095407[x]=A055642[x].

Example

n=184, 3 digits,prime set={2,23} also with 3 digits {2,2,3}.

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, 0]]
Rest[Select[Range[200], Length[Flatten[IntegerDigits/@Transpose[ FactorInteger[ #]][[1]]]]==IntegerLength[#]&]] (* Harvey P. Dale, Oct 22 2011 *)

Crossrefs

Cf. A055642, A095407, A095408, A095409, A095411.

Sequence in context: A175407 A232490 A052414 * A022293 A388999 A183218

Adjacent sequences: A095407 A095408 A095409 * A095411 A095412 A095413

Keyword

base,nonn

Author

Labos Elemer, Jun 21 2004

Status

approved