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A046404 Odd numbers with exactly 2 distinct palindromic prime factors. 4
15, 21, 33, 35, 55, 77, 303, 393, 453, 505, 543, 573, 655, 707, 755, 905, 917, 939, 955, 1057, 1059, 1111, 1119, 1149, 1267, 1337, 1441, 1565, 1661, 1765, 1865, 1915, 1991, 2101, 2181, 2191, 2271, 2361, 2391, 2471, 2611, 2681, 2757, 2787, 3443, 3635, 3785 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..500

MATHEMATICA

dpf2Q[n_]:=Module[{pfs=Transpose[FactorInteger[n]][[1]], a, b}, a=First[pfs]; b=Last[pfs]; PrimeNu[n]==PrimeOmega[n]==2 && a==FromDigits[Reverse[ IntegerDigits[ a]]] && b==FromDigits[Reverse[ IntegerDigits[b]]]]; Select[ Range[1, 3801, 2], dpf2Q] (* Harvey P. Dale, Jul 14 2013 *)

CROSSREFS

Cf. A046315, A046372.

Sequence in context: A128907 A225709 A020162 * A198680 A214044 A177516

Adjacent sequences:  A046401 A046402 A046403 * A046405 A046406 A046407

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Jun 15 1998.

STATUS

approved

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Last modified March 27 13:47 EDT 2017. Contains 284176 sequences.