A022500 Describe the previous term! (method B - initial term is 4).

4, 41, 4111, 4113, 411231, 4112213111, 411222113113, 41122312311231, 4112223111213112213111, 41122331132111311222113113, 411222321231211331122312311231

Offset

1,1

Comments

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

Links

Seiichi Manyama, Table of n, a(n) for n = 1..23

Example

E.g. the term after 4113 is obtained by saying "4 once, 1 twice, 3 once", which gives 411231.

Mathematica

a[1] = 4;
a[n_] := a[n] = {#[[1]], Length[#]}& /@ Split[a[n-1] // IntegerDigits] // Flatten // FromDigits;
Array[a, 11] (* Jean-François Alcover, Jul 13 2016 *)

Crossrefs

Cf. A007651, A022470, A022499, A022501-A022505.

Sequence in context: A006825 A333731 A326899 * A320335 A076652 A078288

Adjacent sequences: A022497 A022498 A022499 * A022501 A022502 A022503

Keyword

nonn,base,easy,nice

Author

N. J. A. Sloane

Status

approved