A022511 Describe previous term from the right (method A - initial term is 7).

7, 17, 1711, 211711, 21172112, 122112172112, 122112171112212211, 2122112231171112212211, 21221122311721132221221112, 12312211321321121721132221221112

Offset

0,1

Comments

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

Links

Michael De Vlieger, Table of n, a(n) for n = 0..21

Example

The term after 1711 is obtained by saying "two 1's, one 7, one 1", which gives 211711.

Mathematica

NestList[FromDigits@ Flatten@ Map[Reverse@ Flatten@ Tally[#] &, Split@ Reverse@ IntegerDigits[#]] &, 7, 9] (* Michael De Vlieger, Dec 16 2021 *)

Crossrefs

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

Sequence in context: A093139 A177366 A138491 * A113613 A070415 A034083

Adjacent sequences: A022508 A022509 A022510 * A022512 A022513 A022514

Keyword

nonn,base,easy,nice

Author

N. J. A. Sloane

Extensions

More terms from Erich Friedman

Status

approved