A022508 Describe previous term from the right (method A - initial term is 4).

4, 14, 1411, 211411, 21142112, 122112142112, 122112141112212211, 2122112231141112212211, 21221122311421132221221112, 12312211321321121421132221221112

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• base
• easy
• nice

Comments

Method A = 'frequency' followed by 'digit'-indication.

Examples

			The term after 1411 is obtained by saying "two 1's, one 4, one 1", which gives 211411.
		

Crossrefs

Cf. A022506, A006711, A022482, A022507-A022513.

Programs

Mathematica

A022508[1]:=4;A022508[n_]:=A022508[n]=FromDigits[Flatten[{Length[#],First[#]}&/@Split[Reverse[IntegerDigits[A022508[n-1]]]]]];Map[A022508,Range[15]] (* Peter J. C. Moses, Apr 22 2013 *)

Extensions

More terms from Erich Friedman