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 A053126 Binomial coefficients binomial(2*n-3,4). 11
 5, 35, 126, 330, 715, 1365, 2380, 3876, 5985, 8855, 12650, 17550, 23751, 31465, 40920, 52360, 66045, 82251, 101270, 123410, 148995, 178365, 211876, 249900, 292825, 341055, 395010, 455126, 521855, 595665, 677040, 766480 (list; graph; refs; listen; history; text; internal format)
 OFFSET 4,1 COMMENTS Number of intersections of diagonals in the interior of regular (2n-3)-gon. - Philippe Deléham, Jun 07 2013 REFERENCES M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings). LINKS Vincenzo Librandi, Table of n, a(n) for n = 4..200 M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]. Milan Janjic, Two Enumerative Functions University of Banja Luka (Bosnia and Herzegovina, 2017). Ângela Mestre, José Agapito, Square Matrices Generated by Sequences of Riordan Arrays, J. Int. Seq., Vol. 22 (2019), Article 19.8.4. FORMULA a(n) = binomial(2*n-3, 4) if n >= 4 else 0; G.f.: (5+10*x+x^2)/(1-x)^5. a(n) = A053123(n,4), n >= 4; a(n) = 0, n=0..3 (fifth column of shifted Chebyshev's S-triangle, decreasing order). a(n) = A006561(2n-3). - Philippe Deléham, Jun 07 2013 E.g.f.: (90 - 84*x + 39*x^2 - 12*x^3 + 4*x^4)*exp(x)/6. - G. C. Greubel, Aug 26 2018 MATHEMATICA Table[Binomial[2*n-3, 4], {n, 4, 50}] (* G. C. Greubel, Aug 26 2018 *) PROG (MAGMA) [Binomial(2*n-3, 4): n in [4..40]]; // Vincenzo Librandi, Oct 07 2011 (PARI) for(n=4, 50, print1(binomial(2*n-3, 4), ", ")) \\ G. C. Greubel, Aug 26 2018 CROSSREFS Cf. A053123, A002492. Sequence in context: A161199 A111877 A179337 * A096743 A026697 A000910 Adjacent sequences:  A053123 A053124 A053125 * A053127 A053128 A053129 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified April 20 01:03 EDT 2021. Contains 343117 sequences. (Running on oeis4.)