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 A130565 #14 Feb 06 2020 19:21:06 %S A130565 1,6,57,650,8184,109668,1533939,22137570,327203085,4928006512, %T A130565 75357373305,1166880131820,18259838103852,288308609783760, %U A130565 4587430875645660,73484989079268690,1184104656043939071 %N A130565 Member k=6 of a family of generalized Catalan numbers. %C A130565 The generalized Catalan numbers C(k,n):= binomial(k*n+1,n)/(k*n+1) become for negative k=-|k|, with |k|>=2, ((-1)^(n-1))*binomial((|k|+1)*n-2,n)/(|k|*n-1), n>=0. %C A130565 For the members of the family C(k,n), k=2..9, see A130564. %C A130565 The family c(k,n):=binomial((k+1)*n-2,n)/(k*n-1), n>=1, has the members A006013, A006632, A118971,for k=2,3,4 respectively (but the offset there is 0) and A130564 for k=5. %H A130565 Harvey P. Dale, <a href="/A130565/b130565.txt">Table of n, a(n) for n = 1..806</a> %H A130565 Elżbieta Liszewska, Wojciech Młotkowski, <a href="https://arxiv.org/abs/1907.10725">Some relatives of the Catalan sequence</a>, arXiv:1907.10725 [math.CO], 2019. %F A130565 a(n) = binomial((k+1)*n-2,n)/(k*n-1), with k=6. %F A130565 G.f.: inverse series of y*(1-y)^6. %F A130565 a(n) = (6/7)*binomial(7*n,n)/(7*n-1). [_Bruno Berselli_, Jan 17 2014] %F A130565 From _Wolfdieter Lang_, Feb 06 2020: (Start) %F A130565 G.f.: (6/7)*(1 - hypergeom([-1, 1, 2, 3, 4, 5]/7, [1, 2, 3, 4, 5]/6, (7^7/6^6)*x)). %F A130565 E.g.f.: (6/7)*(1 - hypergeom([-1, 1, 2, 3, 4, 5]/7, [1, 2, 3, 4, 5, 6]/6, (7^7/6^6)*x)). (End) %t A130565 Table[Binomial[7n-2,n]/(6n-1),{n,20}] (* _Harvey P. Dale_, Feb 25 2013 *) %Y A130565 Cf. k=5 member A130564. A006013, A006632, A118971, %K A130565 nonn,easy %O A130565 1,2 %A A130565 _Wolfdieter Lang_, Jul 13 2007