A070464 - OEIS

%I #19 Dec 18 2023 13:08:48

%S 0,1,4,9,16,25,36,7,22,39,16,37,18,1,28,15,4,37,30,25,22,21,22,25,30,

%T 37,4,15,28,1,18,37,16,39,22,7,36,25,16,9,4,1,0,1,4,9,16,25,36,7,22,

%U 39,16,37,18,1,28,15,4,37,30,25,22,21,22,25,30,37,4,15,28,1,18,37,16,39

%N a(n) = n^2 mod 42.

%H Vincenzo Librandi, <a href="/A070464/b070464.txt">Table of n, a(n) for n = 0..1400</a>

%H <a href="/index/Rec#order_42">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, 1).

%F a(n) = a(n-42). - _G. C. Greubel_, Mar 25 2016

%t Table[Mod[n^2,42],{n,0,200}] (* _Vladimir Joseph Stephan Orlovsky_, Apr 27 2011 *)

%t PowerMod[Range[0,80],2,42] (* _Harvey P. Dale_, Mar 13 2019 *)

%o (Magma) [n^2 mod 42: n in [0..80]]; // _Vincenzo Librandi_, Apr 27 2011

%o (PARI) a(n)=n^2%42 \\ _Charles R Greathouse IV_, Apr 06 2016

%Y Cf. A070461, A070462, A070463.

%K nonn,easy

%O 0,3

%A _N. J. A. Sloane_, May 12 2002