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 A260832 a(n) = numerator(Jtilde2(n)). 35
 1, 3, 41, 147, 8649, 32307, 487889, 1856307, 454689481, 1748274987, 26989009929, 104482114467, 6488426222001, 25239009088827, 393449178700161, 1535897056631667, 1537112996582116041, 6016831929058214523, 94316599529950360769, 369994845516850143483, 23244865440911268112681 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Jtilde2(n) are Apéry-like rational numbers that arise in the calculation of zetaQ(2), the spectral zeta function for the non-commutative harmonic oscillator using a Gaussian hypergeometric function. LINKS G. C. Greubel, Table of n, a(n) for n = 0..830 Takashi Ichinose, Masato Wakayama, Special values of the spectral zeta function of the non-commutative harmonic oscillator and confluent Heun equations, Kyushu Journal of Mathematics, Vol. 59 (2005) No. 1 p. 39-100. Kazufumi Kimoto, Masato Wakayama, Apéry-like numbers arising from special values of spectral zeta functions for non-commutative harmonic oscillators, Kyushu Journal of Mathematics, Vol. 60 (2006) No. 2 p. 383-404 (see Table 1). FORMULA Jtilde2(n) = J2(n)/J2(0) with J2(0) = 3*zeta(2) (normalization). And 4n^2*J2(n) - (8n^2-8n+3)*J2(n-1) + 4(n-1)^2*J2(n-2) = 0 with J2(0) = 3*zeta(2) and J2(1) = 9*zeta(2)/4. Jtilde2(n) = Sum_{k=0..n} (-1)^k*binomial(-1/2,k)^2*binomial(n,k). Jtilde2(n) = Sum_{k=0..n} binomial(2*k,k)*binomial(4*k,2*k)*binomial(2*(n-k),n-k)*binomial(4*(n-k),2*(n-k))/(2^(4*n)*binomial(2*n,n). From Andrey Zabolotskiy, Oct 04 2016: (Start) Jtilde2(n) = Integral_{ x >= 0 } (L_n(x))^2*exp(-x)/sqrt(Pi*x) dx, where L_n(x) is the Laguerre polynomial (A021009). G.f. of Jtilde2(n): 2F1(1/2,1/2;1;z/(z-1))/(1-z). (End) MATHEMATICA Numerator[Table[Sum[ (-1)^k*Binomial[-1/2, k]^2*Binomial[n, k], {k, 0, n}], {n, 0, 50}]] (* G. C. Greubel, Feb 15 2017 *) PROG (PARI) a(n) = numerator(sum(k=0, n, (-1)^k*binomial(-1/2, k)^2*binomial(n, k))); (PARI) a(n) = numerator(sum(k=0, n, binomial(2*k, k)*binomial(4*k, 2*k)* binomial(2*(n-k), n-k)*binomial(4*(n-k), 2*(n-k))) / (2^(4*n)* binomial(2*n, n))); CROSSREFS Cf. A056982 (denominators), A013661 (zeta(2)), A264541 (Jtilde3). The Apéry-like numbers [or Apéry-like sequences, Apery-like numbers, Apery-like sequences] include A000172, A000984, A002893, A002895, A005258, A005259, A005260, A006077, A036917, A063007, A081085, A093388, A125143 (apart from signs), A143003, A143007, A143413, A143414, A143415, A143583, A183204, A214262, A219692, A226535, A227216, A227454, A229111 (apart from signs), A260667, A260832, A262177, A264541, A264542, A279619, A290575, A290576. (The term "Apery-like" is not well-defined.) Sequence in context: A289270 A262555 A106978 * A089131 A057650 A280176 Adjacent sequences:  A260829 A260830 A260831 * A260833 A260834 A260835 KEYWORD nonn,frac AUTHOR Michel Marcus, Nov 17 2015 STATUS approved

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Last modified May 26 09:37 EDT 2020. Contains 334620 sequences. (Running on oeis4.)