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%I #10 Feb 12 2024 12:38:13
%S 1,1,1,1,1,1,1,1,1,1,1,2,4,8,6,3,5,0,9,9,5,3,1,7,7,1,4,6,5,3,8,2,7,9,
%T 1,5,6,9,1,6,0,3,7,6,6,6,7,7,1,3,5,9,9,5,3,1,8,4,2,6,9,1,0,1,7,3,9,2,
%U 5,5,8,3,3,0,7,7,4,1,9,6,5,5,6,4,7,3,8,2,9,1,0,1,1,1,1,1,1,1,1,1,1,2,4,8,6,3,5,0,9,9,5,3,1,7,7,1,4,6,5,3
%N First differences of A080867, modulo 10.
%C Periodic from a(1)=1 onward, with a period of 90 terms.
%H Ray Chandler, <a href="/A080868/b080868.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_90">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
%F a(n) = A080867(n+1)-A080867(n) mod 10.
%p A080868 := n -> ((A080867(n+1)-A080867(n)) mod 10);
%K nonn,base
%O 0,12
%A Laurent Dorey (laurentdorey(AT)wanadoo.fr) and _Antti Karttunen_, Feb 21 2003