A053169 A paradoxical sequence: a positive integer n is in this sequence if and only if n is not in sequence A_n in the database.

4, 7, 9, 11, 12, 13, 15, 17, 18, 20, 21, 22, 23, 24, 25, 28, 29, 30, 31, 32, 33, 34, 35, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 58, 60, 61, 63, 64, 65, 66, 67, 68, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100

Offset: 1

Author

Miklos Szabo (mike(AT)ludens.elte.hu), N. J. A. Sloane, Feb 29 2000

Keywords

• nonn
• nice

Comments

"Not in sequence A_n" means not in the full list of terms, not simply in the list of terms visible in the entry.

The paradox is of course: is 53169 in this sequence?

Examples

			Sequence A000001 contains 1, so 1 is not in the sequence; A000002 contains 2, so 2 is not in the sequence; ...
		

References

• Smullyan, Raymond M, What is the name of this book? : The riddle of Dracula and other logical puzzles, Englewood Cliffs, NJ : Prentice-Hall, c1978, see puzzle 163.

Links

• Index entries for sequences whose definition involves A_n (or An).

Crossrefs

Cf. A107357.

Complement of A053873.

Extensions

Thanks to Alexander Hulpke for the information that 19 is in A000019.

Extended to n=100 by N. J. A. Sloane, May 26 2007