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%I #22 Dec 14 2023 05:17:14
%S 1,3,9,5,7,7,5,9,3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,
%T 7,7,5,9,3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,7,7,5,9,
%U 3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,7,7,5,9,3,1,1,3,9,5,7
%N Digit next to last in squares ending in 6.
%C Entries are always one of the odd digits 1,3,5,7,9.
%C Palindrome of period 10. [From _Paul Curtz_, Jan 04 2009]
%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,-1,1,-1,1,-1,1,-1,1).
%F G.f. -x*(1 +2*x +7*x^2 -2*x^3 +9*x^4 -2*x^5 +7*x^6 +2*x^7 +x^8) / ( (x-1) *(1+x+x^2+x^3+x^4) *(1-x+x^2-x^3+x^4) ). - _R. J. Mathar_, Jul 28 2013
%t Mod[Floor[ #^2/10], 10] & /@ Select[Range[700], Mod[ #^2, 10] == 6 &] (* _Ray Chandler_, May 13 2005 *)
%Y Cf. A000290.
%K nonn,base
%O 1,2
%A _Lekraj Beedassy_, May 10 2005
%E Extended by _Ray Chandler_, May 13 2005
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