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A143583 Apery-like numbers: a(n) = (1/C(2n,n))*sum {k = 0..n} C(2k,k)*C(4k,2k)*C(2n-2k,n-k)*C(4n-4k,2n-2k). 34
1, 12, 164, 2352, 34596, 516912, 7806224, 118803648, 1818757924, 27972399792, 431824158864, 6686855325888, 103814819552016, 1615296581684928, 25180747436810304, 393189646497706752, 6148451986328464164 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

These numbers bear some analogy to the Apery numbers A005258. They appear in the evaluation of the spectral zeta function of the non-commutative harmonic oscillator zeta_Q(s) at s = 2 and satisfy a recurrence relation similar to the one satisfied by the Apery numbers.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

K. Kimoto and M. Wakayama, Apery-like numbers arising from special values of spectral zeta functions for non-commutative harmonic oscillators Kyushu J. Math. Vol. 60, 2006, 383-404.

FORMULA

a(n) = (1/C(2n,n))*sum {k = 0..n} C(2k,k)*C(4k,2k)*C(2n-2k,n-k)*C(4n-4k,2n-2k).

Recurrence relation:

a(0) = 1, a(1) = 12, n^2*a(n) = 4*(8*n^2-8*n+3)*a(n-1) - 256*(n-1)^2*a(n-2).

Congruences:

For odd prime p, a(m*p^r) = a(m*p^(r-1)) (mod p^r) for any m,r in N.

a(n) ~ 16^n/(Pi*sqrt(Pi*n)) * (log(n) + gamma + 6*log(2)), where gamma is the Euler-Mascheroni constant (A001620). - Vaclav Kotesovec, Oct 11 2013

a(n) = sum {k = 0..n} 4^(n-k) C(2k,k)^2*C(2n-2k,n-k). - Tito Piezas III, Dec 12 2014

a(n) = hypergeom([1/2,1/2,n+1],[1,n+3/2],1)*2^(5*n+1)*n!/((2*n+1)!!*Pi) - G. A. Edgar, Dec 10 2016

EXAMPLE

G.f. = 1 + 12*x + 164*x^2 + 2352*x^3 + 34596*x^4 + 516912*x^5 + ...

MAPLE

a := n -> 1/binomial(2n, n)*add(binomial(2k, k)*binomial(4k, 2k)*binomial(2n-2k, n-k)*binomial(4n-4k, 2n-2k), k = 0..n): seq(a(n), n = 0..20):

series( 2*EllipticK(4*x^(1/2))/(Pi*sqrt(1-16*x)), x=0, 20); # Mark van Hoeij, Apr 06 2013

MATHEMATICA

Table[1/Binomial[2*n, n]*Sum[Binomial[2*k, k]*Binomial[4*k, 2*k]*Binomial[2*n-2*k, n-k]*Binomial[4*n-4*k, 2*n-2*k], {k, 0, n}], {n, 0, 20}] (* Vaclav Kotesovec, Oct 11 2013 *)

CROSSREFS

Cf. A005258.

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: A024221 A093152 A282010 * A231541 A203372 A193104

Adjacent sequences:  A143580 A143581 A143582 * A143584 A143585 A143586

KEYWORD

easy,nonn

AUTHOR

Peter Bala, Aug 25 2008

STATUS

approved

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Last modified February 22 06:17 EST 2018. Contains 299430 sequences. (Running on oeis4.)