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 A259853 Denominators of the terms of Lehmer's series S_2(2), where S_k(x) = Sum_{n>=1} n^k*x^n/binomial(2*n, n). 2
 1, 3, 5, 35, 63, 77, 429, 6435, 12155, 46189, 88179, 676039, 1300075, 5014575, 215441, 300540195, 583401555, 756261275, 4418157975, 6892326441, 22427411435, 263012370465, 514589420475, 895766768975, 15801325804719, 61989816618513, 121683714103007 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The first 14 terms are identical to A052468. LINKS F. J. Dyson, N. E. Frankel, M. L. Glasser, Lehmer's Interesting Series, arXiv:1009.4274 [math-ph], 2010-2011. FORMULA a(n) = denominator(n^2*2^n/C(2*n,n)). EXAMPLE 1/1, 8/3, 18/5, 128/35, 200/63, 192/77, 784/429, ... = A259852 / A259853 MATHEMATICA Table[2^n*n^2/Binomial[2*n, n] // Denominator, {n, 1, 40}] PROG (PARI) vector(40, n, denominator(n^2*2^n/binomial(2*n, n))) \\ Michel Marcus, Jul 07 2015 CROSSREFS Cf. A052468, A259852 (numerators), A180875, A014307. Sequence in context: A162444 A305858 A261659 * A052468 A055786 A001790 Adjacent sequences:  A259850 A259851 A259852 * A259854 A259855 A259856 KEYWORD nonn,frac,easy AUTHOR Jean-François Alcover, Jul 07 2015 STATUS approved

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Last modified February 20 21:05 EST 2019. Contains 320347 sequences. (Running on oeis4.)