A046360 Composite palindromes divisible by the palindromic sum of their prime factors (counted with multiplicity).

4, 5445, 234432, 585585, 888888, 951159, 999999, 1345431, 2554552, 4620264, 5842485, 6151516, 9704079, 12333321, 40199104, 42266224, 42666624, 44088044, 46355364, 63599536, 63633636, 420838024, 424848424, 631949136, 649363946

Offset

1,1

Links

Table of n, a(n) for n=1..25.

Example

649363946 = 2 * 7 * 11 * 83 * 101 * 503 -> Sum of factors is palindrome 707 -> 649363946 / 707 = 918478 exactly.

Mathematica

palQ[n_]:= Reverse[x=IntegerDigits[n]] == x; t={}; Do[If[!PrimeQ[n] && And@@palQ/@{n, y=Total[Times@@@FactorInteger[n]]} && IntegerQ[n/y], AppendTo[t, n]], {n, 4, 6*10^6}]; t (* Jayanta Basu, Jun 05 2013 *)
pspfQ[n_]:=Module[{sf=Total[Times@@@FactorInteger[n]]}, CompositeQ[ n] && AllTrue[{n, sf}, PalindromeQ]&&IntegerQ[n/sf]]; Select[Range[ 2, 65*10^7], pspfQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 24 2019 *)

Crossrefs

Cf. A046358, A046359.

Sequence in context: A306962 A102205 A283663 * A367942 A079232 A338665

Adjacent sequences: A046357 A046358 A046359 * A046361 A046362 A046363

Keyword

nonn,base

Author

Patrick De Geest, Jun 15 1998

Extensions

Definition clarified by Harvey P. Dale, Nov 24 2019

Status

approved