OFFSET
1,2
COMMENTS
a(n) never equals a(n+1), by decree.
For the first 719 terms this coincides with the sequence {gcd(A280985(n), A280985(n+1))}. By decree, the latter may not contain two consecutive 1's. - N. J. A. Sloane, Jan 21 2017
LINKS
Rémy Sigrist, Table of n, a(n) for n = 1..10000
MATHEMATICA
f[l_List] := Block[{k = 1, c = GCD[l[[ -1]], l[[ -2]]]}, While[MemberQ[l, k] || GCD[k, l[[ -1]]] == c, k++ ]; Append[l, k]]; GCD @@@ Partition[Nest[f, {1, 2}, 100], 2, 1] (* Ray Chandler, Jan 16 2007 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Jan 08 2007
EXTENSIONS
Extended by Ray Chandler, Jan 16 2007
STATUS
approved