A178889 Numbers n such that R(n) (n-reversed) appears to the left of n in the string 12345678910111213....

19, 21, 29, 31, 32, 39, 41, 42, 43, 49, 51, 52, 53, 54, 59, 61, 62, 63, 64, 65, 69, 71, 72, 73, 74, 75, 76, 79, 81, 82, 83, 84, 85, 86, 87, 89, 91, 92, 93, 94, 95, 96, 97, 98, 99, 101, 110, 111, 119, 120, 121, 130, 131, 140, 141, 150, 151, 160, 161, 170, 171, 180, 181

Offset: 1

Author

Paolo P. Lava & Giorgio Balzarotti, Jun 21 2010

Keywords

• nonn
• base
• easy

Comments

Consider the infinite string of digits A007908(row->infinity). Whenever the digit-reversed variant of n, R(n) = A004086(n), appears ahead of n in that string, adjoin n to the current sequence.

Examples

			19 is generated where 9 meets 10, 12345678(91)01112131415161718(19)20...
21 is generated by 1 and 2: (12)34567891011121314151617181920(21)22...
29 is generated where 19 joins 20: 1234567891011121314151617181(92)02122232425262728(29)30...
		

Crossrefs

Cf. A116700.

Extensions

Definition shortened, examples detailed, keyword:base added by R. J. Mathar, Jul 13 2010