A046457 Concatenation of the 8 prime factors of composite a(n) is a palindrome.

256, 6561, 390625, 2484375, 5764801, 13361565, 25765131, 69090879, 89994375, 110875779, 125919255, 128035545, 188245551, 207847185, 210815759, 214358881, 242810337, 246891183, 246944565, 272828031, 400792119, 464794365, 475376391

Offset: 0

Author

Patrick De Geest, Jul 15 1998

Keywords

• nonn
• base

Examples

			2484375 = 3 * 5 * 5 * 5 * 5 * 5 * 5 * 53 -> 355555553 is palindromic.
		

Crossrefs

Cf. A046447.

Programs

Mathematica

For[n=2,n<1000000,n++,factors=FactorInteger[n]; If[Total[Transpose[factors][[2]]]!=8,Continue[]];digits={}; For[i=1,i<=Length[factors],i++, digits=Join[digits, Flatten[Table[IntegerDigits[factors[[i,1]]],{factors[[i,2]]}]]];]; If[digits==Reverse[digits],Print[n]];]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 17 2006 *)

Extensions

More terms from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 17 2006