A139097 - OEIS

%I #13 Mar 31 2017 20:48:08

%S 0,4,8,13,21,30,36,45,54,63,73,85,95,105,119,137,158,178,200,211,227,

%T 248,268,288,309,325,347,369,390,408,424,445,465,485,506,520,537,559,

%U 579,601,614,632,651,669,688,709,725,747,769,790,808,825,847,869,890,908,924,945,965,985,1006,1020,1037,1059

%N Form a sequence of words as follows: look to the left, towards the beginning of the sequence and write down the number of letters you see; repeat; then replace the words with the corresponding numbers.

%C The sequence of words is: zero, four, eight, thirteen, twenty-one, thirty, ... (in American English).

%C Hyphens and spaces are not counted.

%C This is an English version of the sequence in A139121.

%C a(0) = 0, a(n+1) = a(n) + A005589(a(n)). - _Jonathan Vos Post_, Jun 15 2008

%D E. Angelini, "Jeux de suites", in Dossier Pour La Science, pp. 32-35, Volume 59 (Jeux math'), April/June 2008, Paris.

%H M. F. Hasler, <a href="/A139097/b139097.txt">Table of n, a(n) for n = 0..423</a>

%e The second word is "four" (and so a(2)=4), because at the end of the first word we can see four letters to the left.

%Y Cf. A005589. See A060403 and A139121 for other versions.

%K nonn,word,easy

%O 0,2

%A _Jonathan Vos Post_, May 12 2007

%E Edited by _N. J. A. Sloane_, Jun 08 2008

%E More terms from _M. F. Hasler_ and _R. J. Mathar_, Jun 15 2008