A111185 - OEIS

A111185

Let f(k) denote the largest prime factor of k which is not a palindrome. Sequence gives numbers k such that the sum of the factorials of the digits of k is equal to f(k) reversed.

143, 541, 2105, 2444, 3431, 4144, 4233, 4301, 4440, 10234, 12243, 12341, 20313, 22320, 30422, 34030, 34144, 35140, 46003, 52100, 53013, 102613, 106312, 112413, 113162, 120032, 134046, 200340, 202124, 203112, 210304, 211203, 211232, 212004

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

2105 = 5*'421' and 2! + 1! + 0! + 5! = 124.

MATHEMATICA

r[n_] := FromDigits[Reverse[IntegerDigits[n]]]; np[n_] := (n != r[n]); f[n_] := Plus @@ Map[ #!&, IntegerDigits[n]]; Do[l = Select[First /@ FactorInteger[n], np]; If[Length[l] > 0, k = r[Max[l]]; If[k == f[n], Print[n]]], {n, 1, 10^6}] (* Ryan Propper, Oct 19 2005 *)

CROSSREFS

See A074301 for another version.

Sequence in context: A213337 A156963 A126703 * A074301 A156635 A354483

Adjacent sequences: A111182 A111183 A111184 * A111186 A111187 A111188

KEYWORD

base,nonn

AUTHOR

Jason Earls, Sep 21 2002

EXTENSIONS

More terms from Ryan Propper, Oct 19 2005

STATUS

approved