A139121 Total number of letters in the preceding terms spelled out in French.

0, 4, 10, 13, 19, 26, 34, 46, 57, 70, 81, 94, 113, 123, 137, 151, 168, 184, 205, 217, 232, 250, 267, 287, 310, 322, 340, 357, 379, 403, 418, 435, 455, 478, 503, 516, 529, 546, 565, 585, 608, 619, 633, 651, 671, 692, 715, 729, 746, 765, 785, 808, 820, 833, 852, 873, 895, 920, 933, 952, 973, 995, 1020

Offset: 1

Author

N. J. A. Sloane (based on Angelini's article), Jun 08 2008, Jun 15 2008

Keywords

• nonn
• word

Comments

Form a sequence of French 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 by the corresponding numbers.

The sequence of words is: zero, quatre, dix, treize, dix-neuf, vingt-six, trente-quatre, quarante-six, cinquante-sept, ...

Hyphens, accents and spaces are not counted.

For an English version see A139097.

Examples

			The first word is "zero", because initially there are no letters to the left. The second word is "quatre" (and so a(2)=4), because at the end of the first word we can see four letters to the left. And so on.
		

References

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

Crossrefs

Cf. A005589, A060403, A139097.

Programs

PARI

A139121(n)={ n>1 & return( #select(Vec(French(n=A139121(n-1))),x->x>"@")+n )}  /* see A167507 for French() */  \\ M. F. Hasler, Sep 29 2011

Extensions

Offset and a(9) corrected (according to wording of example) and terms beyond a(9) from M. F. Hasler, Sep 29 2011