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 A053793 #15 Jul 02 2025 16:01:59
%S A053793 0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,
%T A053793 0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,
%U A053793 2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0,0,2,6,5,6,2,0
%N A053793 n^2+n modulo 7.
%C A053793 Pronic residues (mod m) are analogous to quadratic residues.
%C A053793 Periodic with period 7.
%H A053793 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 1).
%t A053793 Table[Mod[n^2+n,7],{n,0,120}] (* _Harvey P. Dale_, Aug 26 2012 *)
%t A053793 LinearRecurrence[{0, 0, 0, 0, 0, 0, 1},{0, 2, 6, 5, 6, 2, 0},105] (* _Ray Chandler_, Aug 26 2015 *)
%o A053793 (PARI) A053793(n)=[0, 2, 6, 5, 6, 2, 0][n%7+1] \\ - _M. F. Hasler_, Aug 27 2012
%K A053793 nonn,easy
%O A053793 0,2
%A A053793 Stuart M. Ellerstein (ellerstein(AT)aol.com), Mar 27 2000
%E A053793 More terms from _James Sellers_, Apr 08 2000