OFFSET
1,2
MATHEMATICA
s[1] = {1, 3, 5, 7};
s[2] = {1, 2, 4, 6};
s[3] = {2, 3, 5, 7};
s[4] = {1, 3, 4, 6};
s[5] = {2, 4, 5, 7};
s[6] = {1, 3, 5, 6};
s[7] = {2, 4, 6, 7};
t[a_] := Flatten[s /@ a];
p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]];
aa = p[4]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Roger L. Bagula, Sep 27 2007
EXTENSIONS
New name from Jason Yuen, Sep 22 2024
STATUS
approved