

A098595


Roman numerals version of the Look and Say sequence (original at A005150).


2



1, 11, 111, 1111, 151, 111511, 111115111, 51151111, 1511115151, 111515115111511, 111115111511115111115111, 51151111151511551151111, 15111155115111511111511115151, 111515111511115111115511515115111511, 1111151115111115151155111511115111511115111115111, 511511111551151115111115111115151151111151511551151111
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OFFSET

1,2


COMMENTS

This sequence is suggested at the link given in point 7 at the bottom of the page, but it is given as: I, II, III, IIII, IIV, IIIIV, IVIIV, ... The 5th term seems to use the "number" followed by "frequency" method (one appears 4 times > "I"//"IV") but the 6th and 7th terms use the usual "frequency"//"number" method.


LINKS

Table of n, a(n) for n=1..16.
T. Sillke, Conway sequence


FORMULA

We write the Roman numerals as I, II, III, IV, V and convert the letters into 1's and 5's for the inclusion in the encyclopedia.


EXAMPLE

a(1)=I=1; a(2)="one I"="II"=11; a(3)=111; a(4)=1111; a(5)="four Is"="IVI"=151; and so on.


MATHEMATICA

A098595[1] = 1; A098595[n_] := A098595[n] = FromDigits[Flatten[{Length[#1] /. {4>{1, 5}, 3>{1, 1, 1}, 2>{1, 1}}, First[#1]} &/@Split[IntegerDigits[A098595[n1]]]]]; Map[A098595, Range[15]] (* Peter J. C. Moses, Apr 22 2013 *)


CROSSREFS

Cf. A005150 for original Look and Say sequence and a number of references.
Sequence in context: A110444 A265380 A114397 * A273978 A077488 A039988
Adjacent sequences: A098592 A098593 A098594 * A098596 A098597 A098598


KEYWORD

base,easy,nonn


AUTHOR

Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 17 2004


EXTENSIONS

More terms from David Wasserman, Feb 25 2008


STATUS

approved



