A139097 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.

0, 4, 8, 13, 21, 30, 36, 45, 54, 63, 73, 85, 95, 105, 119, 137, 158, 178, 200, 211, 227, 248, 268, 288, 309, 325, 347, 369, 390, 408, 424, 445, 465, 485, 506, 520, 537, 559, 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

Offset

0,2

Comments

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

Hyphens and spaces are not counted.

This is an English version of the sequence in A139121.

a(0) = 0, a(n+1) = a(n) + A005589(a(n)). - Jonathan Vos Post, Jun 15 2008

References

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

Links

M. F. Hasler, Table of n, a(n) for n = 0..423

Example

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.

Crossrefs

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

Sequence in context: A312220 A335445 A060403 * A160395 A038793 A036709

Adjacent sequences: A139094 A139095 A139096 * A139098 A139099 A139100

Keyword

nonn,word,easy

Author

Jonathan Vos Post, May 12 2007

Extensions

Edited by N. J. A. Sloane, Jun 08 2008

More terms from M. F. Hasler and R. J. Mathar, Jun 15 2008

Status

approved