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 A294486 #44 Nov 22 2024 08:46:50 %S A294486 1,18,150,980,5670,30492,156156,772200,3719430,17551820,81477396, %T A294486 373173528,1690097500,7582037400,33738060600,149067936720, %U A294486 654576544710,2858667619500,12423860225700,53760146239800,231720014946420,995238809839560,4260800401533000 %N A294486 a(n) = binomial(2*n,n) * (2*n+1)^2. %D A294486 Bruce C. Berndt, Ramanujan's Notebook, Part I, Springer Verlag, 1985. See p. 289, eq. (iii). %D A294486 Jonathan M. Borwein and Peter B. Borwein, Pi and the AGM, Wiley, 1987. See p. 386. %H A294486 Muniru A Asiru, <a href="/A294486/b294486.txt">Table of n, a(n) for n = 0..200</a> %H A294486 Jonathan M. Borwein and Robert M. Corless, <a href="http://www.jstor.org/stable/2589743">Emerging Tools for Experimental Mathematics</a>, The American Mathematical Monthly, Vol. 106, No. 10 (1999), pp. 889-909. See p. 905. %H A294486 Nikita Gogin and Mika Hirvensalo, <a href="https://pca-pdmi.ru/2020/files/10/GoHi2020ExtAbstract.pdf">On the Moments of Squared Binomial Coefficients</a>, (2020). %H A294486 Bruno Haible and Thomas Papanikolaou, <a href="https://doi.org/10.1007/BFb0054873">Fast multiprecision evaluation of series of rational numbers</a>, in: J. P. Buhler (ed.), Algorithmic Number Theory, ANTS 1998, Lecture Notes in Computer Science, Vol. 1423, Springer, Berlin, Heidelberg, 1998, pp. 338-350, <a href="https://ginac.de/CLN/binsplit.pdf">alternative link</a>. %F A294486 a(n) = A000984(n) * A016754(n). %F A294486 Sum_{n>=0} 1/a(n) = (8*C - Pi*log(2 + sqrt(3)))/3, where C is Catalan's constant, A006752. [Found by Ramanujan. See Berndt, 1985. - _Amiram Eldar_, Jan 27 2024] %F A294486 G.f.: (1 + 8*x)/(1 - 4*x)^(5/2). - _Ilya Gutkovskiy_, Jan 23 2018 %F A294486 Sum_{n>=0} (-1)^n/a(n) = Pi^2/6 - 3*log(phi)^2 = A145436. - _Amiram Eldar_, Oct 19 2020 %F A294486 a(n) = Sum_{k = 0..2*n+1} (-1)^(n+k+1) * k^2 * binomial(2*n+1,k)^2. Cf. A361719. - _Peter Bala_, Mar 24 2023 %F A294486 Sum_{n>=0} A002878(n)/a(n) = (8*G - Pi*log((10+sqrt(50-22*sqrt(5)))/(10-sqrt(50-22*sqrt(5)))))/5, where G is Catalan's constant (A006752) (found by David Bradley, see Borwein and Corless, 1999). - _Amiram Eldar_, Jan 27 2024 %F A294486 D-finite with recurrence n*a(n) +2*(2*n-11)*a(n-1) +16*(-2*n+1)*a(n-2)=0. - _R. J. Mathar_, Nov 22 2024 %p A294486 seq(binomial(2*n, n) * (2*n + 1)^2, n=0..30); # _Muniru A Asiru_, Jan 23 2018 %t A294486 Array[Binomial[2 #, #] (2 # + 1)^2 &, 23, 0] (* _Michael De Vlieger_, Nov 01 2017 *) %o A294486 (PARI) a(n) = binomial(2*n, n) * (2*n+1)^2 %o A294486 (GAP) sequence := List([0..10], n-> Binomial(2*n, n) * (2*n + 1)^2); # _Muniru A Asiru_, Jan 23 2018 %o A294486 (Magma) [Binomial(2*n,n)*(2*n+1)^2: n in [0..30]]; // _G. C. Greubel_, Aug 25 2018 %Y A294486 Cf. A000984, A002878, A006752, A016754, A145436, A361719. %K A294486 nonn,easy %O A294486 0,2 %A A294486 _Daniel Suteu_, Oct 31 2017