This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A014390 #25 Jul 08 2025 05:38:14
%S A014390 1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,
%T A014390 43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,49,43,1,7,
%U A014390 49,43,1,7,49,43,1,7,49,43,1,7
%N A014390 Final 2 digits of 7^n.
%H A014390 Vincenzo Librandi, <a href="/A014390/b014390.txt">Table of n, a(n) for n = 0..1000</a>
%H A014390 <a href="/index/Fi#final">Index entries for sequences related to final digits of numbers</a>
%H A014390 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,-1,1).
%F A014390 a(n) = 7^n mod 50. [_Zerinvary Lajos_, Nov 27 2009]
%t A014390 PowerMod[7,Range[0,70],100] (* _Harvey P. Dale_, Jan 23 2012 *)
%t A014390 LinearRecurrence[{1,-1,1},{1,7,49},70] (* _Harvey P. Dale_, May 09 2018 *)
%o A014390 (Sage) [power_mod(7,n,50)for n in range(0,80)] # _Zerinvary Lajos_, Nov 27 2009
%o A014390 (PARI) a(n)=lift(Mod(7,100)^n) \\ _Charles R Greathouse IV_, Jan 02 2013
%o A014390 (Magma) [Modexp(7, n, 100): n in [0..110]]; // _Vincenzo Librandi_, Aug 16 2016
%K A014390 nonn,easy
%O A014390 0,2
%A A014390 _N. J. A. Sloane_