cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A140291 Erroneous version of A118561.

Original entry on oeis.org

1, 3, 7, 9, 13, 15, 31, 37, 51, 73, 99, 111, 115, 133, 141, 151
Offset: 1

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Author

Keywords

A309406 Absolute lucky numbers: every permutation of digits is a lucky number.

Original entry on oeis.org

1, 3, 7, 9, 13, 15, 31, 33, 37, 51, 73, 99, 111, 115, 151, 339, 393, 511, 777, 933, 9999, 33333, 55555, 111111, 777777, 7777777, 55555555
Offset: 1

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Author

Hauke Löffler, Jul 29 2019

Keywords

Comments

More terms are in A031882, as A031882 is a subset of this sequence.
No more terms below 10^9. - Amiram Eldar, Nov 16 2019

Examples

			a(6) = 15 because 15 and 51 are lucky numbers.
a(14) = 115 because (115, 151, 511) are all lucky numbers.

Crossrefs

Cf. A000959, A118561, A031882, A003459.

Extensions

a(25)-a(27) from Amiram Eldar, Nov 16 2019

A217252 Lucky numbers whose digital reversal is another lucky number.

Original entry on oeis.org

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
Offset: 1

Views

Author

M. F. Hasler, Mar 16 2013

Keywords

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

Crossrefs

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

Formula

A217252 = A118561 \ A031161 = A118561 \ A002113 = A118561 intersect A029742 = { n in A000959 | R(n) is in A000959 and different from n }, where R = A004086.
Showing 1-3 of 3 results.

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