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A046350 Odd composite numbers with only palindromic prime factors. 3
9, 15, 21, 25, 27, 33, 35, 45, 49, 55, 63, 75, 77, 81, 99, 105, 121, 125, 135, 147, 165, 175, 189, 225, 231, 243, 245, 275, 297, 303, 315, 343, 363, 375, 385, 393, 405, 441, 453, 495, 505, 525, 539, 543, 567, 573, 605, 625, 655, 675, 693, 707, 729, 735, 755 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MATHEMATICA

palQ[n_]:=Reverse[x=IntegerDigits[n]]==x; Select[Range[9, 755, 2], !PrimeQ[#]&&And@@palQ/@First/@FactorInteger[#]&] (* Jayanta Basu, Jun 05 2013 *)

Select[Range[9, 800, 2], CompositeQ[#]&&AllTrue[FactorInteger[#][[All, 1]], PalindromeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 08 2018 *)

CROSSREFS

Cf. A033620, A046349, A046351.

Sequence in context: A155474 A100819 A046446 * A225438 A175076 A046337

Adjacent sequences:  A046347 A046348 A046349 * A046351 A046352 A046353

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Jun 15 1998.

STATUS

approved

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Last modified November 16 04:54 EST 2018. Contains 317257 sequences. (Running on oeis4.)