A139212 Number of vowels in the preceding terms spelled out in French.

0, 2, 4, 7, 8, 10, 11, 13, 16, 19, 22, 25, 27, 29, 32, 36, 39, 43, 49, 55, 60, 64, 71, 78, 85, 90, 95, 102, 105, 107, 109, 112, 116, 120, 122, 126, 129, 133, 138, 143, 150, 155, 161, 168, 175, 183, 190, 196, 204, 210, 214, 221, 227, 232, 239, 246, 254, 264, 274, 285, 293, 303, 308, 313, 319, 325, 330, 335, 341, 350, 357, 365, 373, 383

Offset: 1

Author

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

Keywords

• nonn
• word
• easy

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 vowels you see; repeat; then replace the words by the corresponding numbers.

The sequence of words is: zero, deux, quatre, sept, huit, dix, onze, treize, seize, ...

Hyphens, accents and spaces are not counted.

Examples

			The second word is "deux" (and so a(2)=2 for the 'e' and the 'u'), because at the end of the first word ("zéro") we can see two vowels ('e' and 'o') to the left.
		

References

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

Crossrefs

For an English version see A139282.

Programs

PARI

a(n)={ n>1 || return;#select(Vec(French(n=a(n-1))),x->setsearch(Vec("aeiou"),x))+n }  /* see A167507 for French() */
/* Version with memoization for better performance when n >> 100: */
A139212(n)={ type(a139212)!="t_VEC" && a139212=[];
n > #a139212 && a139212=concat( a139212,vector(n-#a139212));
(a139212[n] || n==1) && return(a139212[n]);
a139212[n]=/*up to here only memoization, could be omitted*/
#select(Vec(French(A139212(n-1))), x->setsearch(Vec("aeiou"),x))) + A139212(n-1) } \\ M. F. Hasler, Sep 29 2011

Extensions

Fixed offset (according to example) and typo in example. M. F. Hasler, Sep 29 2011