OFFSET
1,3
REFERENCES
M. Archibald, A. Blecher and A. Knopfmacher, Fixed points in compositions and words, accepted by the Journal of Integer Sequences.
LINKS
M. Archibald, A. Blecher, and A. Knopfmacher, Fixed Points in Compositions and Words, J. Int. Seq., Vol. 23 (2020), Article 20.11.1.
FORMULA
G.f.: x*(1-x)^3/((1-2*x)*(1-x-x^2)^2).
EXAMPLE
For n=3 the a(3)=4 values are the first 1 in the composition 111 and both values in the composition 12 (the compositions 21 and 3 have no fixed points).
PROG
(PARI) Vec((x*(1-x)^3)/((1-2*x)*(1-x-x^2)^2) + O(x^40)) \\ Michel Marcus, Jun 18 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Margaret Archibald, Jun 18 2020
EXTENSIONS
More terms from Michel Marcus, Jun 18 2020
STATUS
approved