OFFSET
1,2
MATHEMATICA
f[s_] := Block[{k = 1, l = Take[s, -4]}, While[ Union[ GCD[k, l]] != {1} || MemberQ[s, k], k++]; Append[s, k]]; Nest[f, {1, 2, 3, 4}, 70]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Jun 26 2011
STATUS
approved