OFFSET
0,3
LINKS
N. J. A. Sloane, Table of n, a(n) for n = 0..100
Frederic Chyzak, Enumerating alcohols and other classes of chemical molecules
MAPLE
The following Maple commands are taken from the Chyzak web site:
with(combstruct);
gramm_Alkyl:=Alkyl=Prod(Carbon, Set(Alkyl, card<=3)), Carbon=Atom:
specs_Alkyl:=[Alkyl, {gramm_Alkyl}, unlabeled]:
gramm_S1_Alkyl:=S1_Alkyl[X]=Union(Prod(Carbon, S1_Alkyl[X], Set(Alkyl, card<=2)), Prod(Prod(Carbon, X), Set(Alkyl, card<=2))), X=Epsilon:
specs_S1_Alkyl:=[S1_Alkyl[X], {gramm_S1_Alkyl, gramm_Alkyl}, unlabeled]:
gramm_S2b_Alkyl:=S2_Alkyl[X, X]=Union(Prod(Carbon, S2_Alkyl[X, X], Set(Alkyl, card<=2)), Prod(Carbon, Union(Prod(S1_Alkyl[X], S1_Alkyl[X]), Prod(S1_Alkyl[X], X), Prod(X, X)), Set(Alkyl, card<=1))):
specs_S2b_Alkyl:=[S2_Alkyl[X, X], {gramm_S2b_Alkyl, gramm_S1_Alkyl, gramm_Alkyl}, unlabeled]:
[seq(count(specs_S2b_Alkyl, size=i), i=0..50)];
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 14 2008
STATUS
approved