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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

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..22.

EXAMPLE

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

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 *)

CROSSREFS

Cf. A046447.

Sequence in context: A351606 A343288 A050755 * A179645 A056585 A321818

Adjacent sequences: A046454 A046455 A046456 * A046458 A046459 A046460

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Jul 15 1998

EXTENSIONS

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

STATUS

approved

URL: https://oeis.org/A046457

⇱ A046457 - OEIS