A217252 - OEIS

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A217252

Lucky numbers whose digital reversal is another lucky number.

13, 15, 31, 37, 51, 73, 115, 133, 163, 169, 189, 193, 195, 327, 331, 339, 361, 385, 391, 399, 511, 529, 537, 579, 583, 591, 723, 729, 735, 739, 925, 927, 933, 937, 961, 975, 981, 993

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Inspired by the error in A140291 (forgotten palindromes 33 and 99), pointed out by L. Edson Jeffery in a post to the SeqFan list.

This sequence is obtained from A118561 by removal of the palindromes A031161 = (1, 3, 7, 9, 33, 99, 111, 141, 151, 171, 303, 393, 535, 717, 727, 777, 787, 979, ...)

By analogy with the "emirps" A006567 and "emirpimes" A097393, these might be called "ykcul"s, for lucky numbers which, when reversed, are different lucky numbers.

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

A217252 = A118561 \ A031161 = A118561 \ A002113 = A118561 intersect A029742 = { n in A000959 | R(n) is in A000959 and different from n }, where R = A004086.

CROSSREFS

Cf. A000959, A002385, A006567, A097393, A029742, A031161, A002113, A118561, A140291.

Sequence in context: A371287 A113801 A108257 * A299593 A318543 A302001

Adjacent sequences: A217249 A217250 A217251 * A217253 A217254 A217255

KEYWORD

base,nonn

AUTHOR

M. F. Hasler, Mar 16 2013

STATUS

approved