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A279108 Numbers n such that greatest prime dividing n = greatest prime dividing R(n), where R(n) is the digit reversal of n and n is a nonpalindromic number. 1
18, 27, 50, 70, 72, 81, 110, 132, 198, 220, 231, 264, 297, 330, 396, 440, 462, 495, 500, 528, 540, 550, 594, 660, 693, 700, 770, 792, 825, 880, 891, 990, 1010, 1066, 1089, 1100, 1107, 1110, 1210, 1212, 1310, 1313, 1320, 1332, 1410, 1414, 1443, 1452, 1510, 1515, 1572, 1584, 1610, 1616, 1665, 1692, 1710, 1717, 1810, 1818, 1910, 1919, 1980, 1998 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that A006530(n) = A006530(A004086(n)) and A136522(n) = 0.

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..2337

Eric Weisstein's World of Mathematics, Greatest Prime Factor

EXAMPLE

18 is in the sequence because 18 is a nonpalindromic number, 18 = 2*3^2, 81 = 3^4 and gpf(18) = gpf(81) = 3.

MATHEMATICA

Select[Range[2000], FactorInteger[#][[-1, 1]] == FactorInteger[FromDigits[Reverse[IntegerDigits[#]]]][[-1, 1]] && !PalindromeQ[#] & ]

CROSSREFS

Cf. A004086, A006530, A136522.

Sequence in context: A109911 A239878 A065751 * A038632 A138336 A166630

Adjacent sequences:  A279105 A279106 A279107 * A279109 A279110 A279111

KEYWORD

nonn,base

AUTHOR

Ilya Gutkovskiy, Dec 06 2016

STATUS

approved

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Last modified March 22 17:25 EDT 2019. Contains 321422 sequences. (Running on oeis4.)