

A221372


A twodigit LookandSay sequence starting with 19: each term summarizes the increasing twodigit substrings of the previous term.


6



19, 119, 111119, 411119, 311119141, 311114119131141191, 611113214219231241291, 311212113114119221123124129131132141142161191192, 911512313314116319521122123124129431132341142161291292
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OFFSET

0,1


COMMENTS

a(16) is the first term containing a zero; this is due to the fact that a(15) is the first term having exactly 10 occurrences of a twodigit number, namely 10 x 51.


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..1000
Eric Weisstein's World of Mathematics, Look and Say Sequence
Wikipedia, Lookandsay sequence
Reinhard Zumkeller, Haskell program for twodigit LookandSay sequences


EXAMPLE

a(0) = 19: 1 x 19 > a(1) = 119;
a(1) = 119: 1 x 11 and 1 x 19 > a(2) = 111119;
a(2) = 111119: 4 x 11 and 1 x 19 > a(3) = 411119;
a(3) = 411119: 3 x 11, 1 x 19 and 1 x 41 > a(4) = 311119141.


PROG

(Haskell) See Link.


CROSSREFS

Cf. A005151, A047842.
Cf. A209234 (start=10), A209233 (start=11), A221368 (start=12), A221369 (start=13), A221373 (start=99).
Sequence in context: A044351 A044732 A159851 * A252924 A157340 A252054
Adjacent sequences: A221369 A221370 A221371 * A221373 A221374 A221375


KEYWORD

nonn,base


AUTHOR

Reinhard Zumkeller, Jan 13 2013


STATUS

approved



