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 A111952 #23 Jun 29 2025 05:28:09 %S A111952 0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5,1, %T A111952 4,0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5, %U A111952 1,4,0,3,6,2,5,1,4,0,3,6,2,5,1,4,0,3,6,2,5,1 %N A111952 a(n) = 3*n mod 7. %C A111952 Period 7: repeat [0, 3, 6, 2, 5, 1, 4]. %C A111952 Draw a regular heptagon with vertices labeled 0..6 going clockwise. Choose any seven consecutive values of a(n) and connect the corresponding vertices in that order with straight lines. This results in a clockwise-inscribed seven-pointed star that remains unbroken during construction. - _Wesley Ivan Hurt_, Apr 10 2015 %H A111952 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,1). %F A111952 G.f.: (3*x+6*x^2+2*x^3+5*x^4+x^5+4*x^6)/(1-x^7). %F A111952 a(n) = mod(n*(7*n-1)/2, 7) = mod(A022264(n), 7). %F A111952 Recurrence: a(n) = a(n-7) for n > 6. - _Wesley Ivan Hurt_, Apr 10 2015 %F A111952 a(n) = (21 + 4*(n mod 7) - 3*((n+1) mod 7) + 4*((n+2) mod 7) - 3*((n+3) mod 7) + 4*((n+4) mod 7) - 3*((n+5) mod 7) - 3*((n+6) mod 7))/7. - _Wesley Ivan Hurt_, Dec 23 2016 %F A111952 a(n) = A010876(3*n). - _R. J. Mathar_, Jan 15 2021 %p A111952 A111952:=n->3*n mod 7: seq(A111952(n), n=0..100); # _Wesley Ivan Hurt_, Apr 10 2015 %t A111952 Mod[3 Range[0, 100], 7] (* _Wesley Ivan Hurt_, Apr 10 2015 *) %o A111952 (PARI) a(n)=3*n%7 \\ _Charles R Greathouse IV_, Jul 23 2011 %o A111952 (Magma) [3*n mod 7 : n in [0..100]]; // _Wesley Ivan Hurt_, Apr 10 2015 %Y A111952 Cf. A022264. %K A111952 easy,nonn %O A111952 0,2 %A A111952 _Paul Barry_, Aug 22 2005