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 A053157 #17 Jan 29 2023 19:32:34
%S A053157 1,5,32,235,1816,14055,107052,800315,5886416,42739855,307295572,
%T A053157 2193374595,15571898616,110121224855,776543100092,5464689616075,
%U A053157 38398915520416,269529406433055,1890416947176612,13251578251332755
%N A053157 Number of 3-element intersecting families (with not necessarily distinct sets) whose union is an n-element set.
%D A053157 V. Jovovic, G. Kilibarda, On the number of Boolean functions in the Post classes F^{mu}_8, Diskretnaya Matematika, 11 (1999), no. 4, 127-138 (translated in Discrete Mathematics and Applications, 9, (1999), no. 6).
%H A053157 G. C. Greubel, <a href="/A053157/b053157.txt">Table of n, a(n) for n = 1..1000</a>
%H A053157 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (22,-190,820,-1849,2038,-840).
%F A053157 a(n) = (7^n -3*5^n +3*4^n +2*3^n -3*2^n +2)/6.
%F A053157 G.f.: -x*(280*x^5-475*x^4+339*x^3-112*x^2+17*x-1)/((x-1)*(2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(7*x-1)). - _Colin Barker_, Jul 29 2012
%t A053157 Table[(7^n -3*5^n +3*4^n +2*3^n -3*2^n +2)/6, {n,1,50}] (* _G. C. Greubel_, Oct 07 2017 *)
%o A053157 (PARI) for(n=1,50, print1((7^n -3*5^n +3*4^n +2*3^n -3*2^n +2)/6, ", ")) \\ _G. C. Greubel_, Oct 07 2017
%o A053157 (Magma) [(7^n -3*5^n +3*4^n +2*3^n -3*2^n +2)/6: n in [1..50]]; // _G. C. Greubel_, Oct 07 2017
%Y A053157 Cf. A051180.
%K A053157 easy,nonn
%O A053157 1,2
%A A053157 _Vladeta Jovovic_, Goran Kilibarda, Feb 28 2000