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.

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

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: A345309 A337752 A379146 * A038632 A138336 A349485

Adjacent sequences: A279105 A279106 A279107 * A279109 A279110 A279111

Keyword

nonn,base

Author

Ilya Gutkovskiy, Dec 06 2016

Status

approved