A001143 Describe the previous term! (method A - initial term is 6).

6, 16, 1116, 3116, 132116, 1113122116, 311311222116, 13211321322116, 1113122113121113222116, 31131122211311123113322116, 132113213221133112132123222116

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base
• easy
• nice

Comments

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

a(n+1) - a(n) is divisible by 10^5 for n > 5. - Altug Alkan, Dec 04 2015

Examples

			The term after 3116 is obtained by saying "one 3, two 1's, one 6", which gives 132116.
		

References

• S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 452-455.
• I. Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 4.

Links

• T. D. Noe, Table of n, a(n) for n = 1..20
• J. H. Conway, The weird and wonderful chemistry of audioactive decay, in T. M. Cover and Gopinath, eds., Open Problems in Communication and Computation, Springer, NY 1987, pp. 173-188.
• S. R. Finch, Conway's Constant. [Broken link]
• S. R. Finch, Conway's Constant. [From the Wayback Machine]

Crossrefs

Cf. A001155, A005150, A006751, A006715, A001140, A001141, A001145, A001151, A001154.

Programs

Mathematica

RunLengthEncode[ x_List ] := (Through[ {First, Length}[ #1 ] ] &) /@ Split[ x ]; LookAndSay[ n_, d_:1 ] := NestList[ Flatten[ Reverse /@ RunLengthEncode[ # ] ] &, {d}, n - 1 ]; F[ n_ ] := LookAndSay[ n, 6 ][ [ n ] ]; Table[ FromDigits[ F[ n ] ], {n, 1, 11} ] (* Zerinvary Lajos, Mar 21 2007 *)