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

1,2

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.

References

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

Links

Table of n, a(n) for n=1..74.

Example

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.

Prog

(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

Crossrefs

For an English version see A139282.

Sequence in context: A013153 A075663 A325419 * A175282 A127875 A056231

Adjacent sequences: A139209 A139210 A139211 * A139213 A139214 A139215

Keyword

nonn,word,easy

Author

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

Extensions

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

Status

approved