A121994 - OEIS

A121994

Smallest natural number that yields a sequence of n decreasing numbers under the "Look and Say" operator A045918.

%I #13 Feb 09 2023 14:49:58

%S 1,33,333,333111,33333333333333333333333333333333311111111111

%N Smallest natural number that yields a sequence of n decreasing numbers under the "Look and Say" operator A045918.

%C a(5) <= 33333333333333333333333333333333 '3's concatenated with 1111111111 '1's. - _Tyler Busby_, Feb 07 2023

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/LookandSaySequence.html">Look and Say</a>.

%e a(3)=333111 because under the Look and Say operator sequence A045918 it yields: 3331, 3311, 2321 which are all decreasing (3 in a row). The next term would be 12131211 which is greater than 2321.

%Y Cf. A045918, A005150, A005341, A023989, A079475.

%K hard,more,nonn,base

%O 0,2

%A _Sergio Pimentel_, Sep 11 2006

%E a(4) from _Sergio Pimentel_, Mar 05 2008

%E a(4) corrected by _Tyler Busby_, Feb 07 2023