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 A095155 #30 Mar 18 2024 16:47:04
%S A095155 7,4977,711326,63602770,4709047749,320401872035,20951777849212,
%T A095155 1344192783541860,85442420316605891,5406486257577661333,
%U A095155 341342273242841583258,21527330224106110255670,1356927944579525164818433,85508356311211819638169671,5387705299223777670172444664
%N A095155 Number of 6-block covers of a labeled n-set.
%H A095155 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (120,-4593,69688,-428787,978768,-615195).
%F A095155 a(n) = (1/6!)*(-1764+1624*3^n-735*7^n+175*15^n-21*31^n+63^n).
%F A095155 G.f.: 7*x^3*(87885*x^3+20891*x^2+591*x+1) / ((x-1)*(3*x-1)*(7*x-1)*(15*x-1)*(31*x-1)*(63*x-1)). - _Colin Barker_, Jul 12 2013
%F A095155 a(n) = sum(i=0..n, (-1)^i * C(n,i) * C(2^(n-i)-1,6) ). - _Geoffrey Critzer_, Aug 24 2014
%F A095155 a(n) = 120*a(n-1)-4593(n-2)+69688*a(n-3)-428787*a(n-4)+978768*a(n-5)-615195*a(n-6). - _Wesley Ivan Hurt_, Aug 26 2014
%p A095155 A095155:=n->(-1764+1624*3^n-735*7^n+175*15^n-21*31^n+63^n)/720: seq(A095155(n), n=3..20); # _Wesley Ivan Hurt_, Aug 26 2014
%t A095155 nn = 19; Table[ Sum[(-1)^i Binomial[n, i] Binomial[2^(n - i) - 1, 6], {i, 0, n}], {n, 3, nn}] (* _Geoffrey Critzer_, Aug 24 2014 *)
%t A095155 Table[(-1764 + 1624*3^n - 735*7^n + 175*15^n - 21*31^n + 63^n)/720, {n, 3, 20}] (* _Wesley Ivan Hurt_, Aug 26 2014 *)
%o A095155 (Magma) [(-1764+1624*3^n-735*7^n+175*15^n-21*31^n+63^n)/720 : n in [3..20]]; // _Wesley Ivan Hurt_, Aug 26 2014
%Y A095155 Column of A055154.
%K A095155 easy,nonn
%O A095155 3,1
%A A095155 _Vladeta Jovovic_, May 31 2004
%E A095155 More terms from _Colin Barker_, Jul 12 2013