The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A046450 Concatenation of prime factors of palindromic composite is a palindrome. 4
 4, 8, 9, 121, 343, 1331, 10001, 10201, 14641, 36763, 1030301, 1037301, 1226221, 9396939, 104060401, 12467976421, 14432823441, 93969696939, 119092290911, 1030507050301, 1120237320211, 1225559555221, 1234469644321, 1334459544331, 100330272033001, 101222252222101 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..26. EXAMPLE E.g., 14432823441 = 3 * 3 * 281 * 313 * 18233 -> 3328131318233 is palindromic. MATHEMATICA d[n_] := IntegerDigits[n]; co[n_, k_] := Nest[Flatten[d[{#, n}]] &, n, k - 1]; t = {}; Do[If[! PrimeQ[n] && Reverse[x = d[n]] == x && Reverse[y = Flatten[d[co @@@ FactorInteger[n]]]] == y, AppendTo[t, n]], {n, 2, 10^7}]; t (* Jayanta Basu, Jun 24 2013 *) CROSSREFS Cf. A046447, A046448, A046449. Sequence in context: A128827 A075786 A348429 * A077271 A084093 A072037 Adjacent sequences: A046447 A046448 A046449 * A046451 A046452 A046453 KEYWORD nonn,base AUTHOR Patrick De Geest, Jul 15 1998 EXTENSIONS Corrected by Charles R Greathouse IV, Apr 23 2010 a(18)-a(24) from Donovan Johnson, May 03 2010 a(25)-a(26) from Donovan Johnson, Aug 09 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 4 10:09 EDT 2023. Contains 365874 sequences. (Running on oeis4.)