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%I #10 Mar 14 2015 17:59:14
%S 1,2,3,2,3,4,5,2,3,2,3,4,3,4,5,2,3,4,5,6,5,2,3,4,3,4,5,2,3,4,5,2,3,2,
%T 3,4,3,4,5,6,7,8,5,6,5,2,3,4,3,4,5,2,3,4,5,2,3,2,3,4,3,4,5,6,7,2,3,4,
%U 3,2,3,4,3,4,5,2,3,4,5,6,5,2,3,4,3,4,5,2,3,4,5,2,3,2,3,4,3,4,5,6,7,2,3,4,3
%N a(1)=1. a(n) = GCD(n,a(n-1)) + GCD(n+1,a(n-1)).
%C First occurrence of k: 1, 2, 3, 6, 7, 20, 41, 42, 127, 1304, 1809, 2530, 2531, 42132, 113413, 113414, 196575, 3160096, 3160097, 3160098, 3160099, 3160100, 3160101, ..., . - _Robert G. Wilson v_, Nov 07 2006
%p a[1]:=1: for n from 2 to 130 do a[n]:=gcd(n,a[n-1])+gcd(n+1,a[n-1]) od: seq(a[n],n=1..130); # _Emeric Deutsch_, Nov 06 2006
%t a[1] = 1; a[n_] := a[n] = GCD[n, a[n - 1]] + GCD[n + 1, a[n - 1]]; Array[a, 105] (* _Robert G. Wilson v_ *)
%K nonn
%O 1,2
%A _Leroy Quet_, Nov 05 2006
%E More terms from _Emeric Deutsch_ and _Robert G. Wilson v_, Nov 06 2006
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