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Revision History for A001790 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Numerators in expansion of 1/sqrt(1-x).
(history; published version)
#236 by Charles R Greathouse IV at Sun Feb 16 08:32:24 EST 2025
LINKS

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/BinomialSeries.html">Binomial Series</a>.

Eric Weisstein's World of Mathematics, <a href="httphttps://mathworld.wolfram.com/LegendrePolynomial.html">Legendre Polynomial</a>.

Discussion
Sun Feb 16
08:32
OEIS Server: https://oeis.org/edit/global/3014
#235 by Joerg Arndt at Sun Dec 29 08:51:01 EST 2024
STATUS

reviewed

approved

#234 by Michel Marcus at Sun Dec 29 08:38:00 EST 2024
STATUS

proposed

reviewed

#233 by Stefano Spezia at Sun Dec 29 07:26:56 EST 2024
STATUS

editing

proposed

#232 by Stefano Spezia at Sun Dec 29 07:18:14 EST 2024
LINKS

W. G. Bickley and J. C. P. Miller, <a href="/A002551/a002551.pdf">Numerical differentiation near the limits of a difference table</a> [Annotated scanned copy].

J. Ser, <a href="/A002720/a002720.pdf">Les Calculs Formels des Séries de Factorielles</a> (Annotated scans of some selected pages).

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/BinomialSeries.html">Binomial Series</a>.

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/LegendrePolynomial.html">Legendre Polynomial</a>.

#231 by Stefano Spezia at Sun Dec 29 06:16:39 EST 2024
REFERENCES

Jerome Spanier and Keith B. Oldham, "Atlas of Functions", Hemisphere Publishing Corp., 1987, chapter 6, equation 6:14:6 at page 51.

STATUS

approved

editing

#230 by Michael De Vlieger at Tue Sep 24 09:29:16 EDT 2024
STATUS

reviewed

approved

#229 by Joerg Arndt at Tue Sep 24 02:26:36 EDT 2024
STATUS

proposed

reviewed

#228 by G. C. Greubel at Mon Sep 23 23:39:13 EDT 2024
STATUS

editing

proposed

#227 by G. C. Greubel at Mon Sep 23 23:37:19 EDT 2024
COMMENTS

Also numerator of binomial(2n,n)/4^n (cf. A046161).

Also the numerator of binomial(2n,2*n,n)/2^n. - T. D. Noe, Nov 29 2005

The convolution of sequence binomial(2n,2*n,n)/4^n with itself is the constant sequence with all terms = 1.

a(n) = denominator of 2^n*n!*n!/(2*n)!. - Artur Jasinski, Nov 26 2011

a(n) = numerator of (1/Pi)*Integral_{x=-oo..+oo} 1/(x^2-2x2*x+2)^n dx. - Leonid Bedratyuk, Nov 17 2012

FORMULA

a(n) = numerator( binomial(2*n,n)/4^n ) (cf. A046161).

a(n) = A000984(n)/A001316(n) where A001316(n) is the highest power of 2 dividing C(2n, 2*n, n) = A000984(n). - Benoit Cloitre, Jan 27 2002

a(n) = denominator of (2^n/binomial(2*n,n)). - Artur Jasinski, Nov 26 2011

a(n) = A001803(n)/(2*n+1). - G. C. Greubel, Sep 23 2024

EXAMPLE

binomial(2n,2*n,n)/4^n => 1, 1/2, 3/8, 5/16, 35/128, 63/256, 231/1024, 429/2048, 6435/32768, ...

PROG

(Magma)

A001790:= func< n | Numerator((n+1)*Catalan(n)/4^n) >;

[A001790(n): n in [0..40]]; // G. C. Greubel, Sep 23 2024

CROSSREFS

Cf. A000142, A000984, A001147, A001316, A001800, A001801, A008316, A046161A001803.

Cf. A005187, A007814, A008316, A046161, A056040, A086117, A094638.

Cf. A101926, A123854, A273194, A344402.

Cf. A060818 (denominator of binomial(2*n,n)/2^n), A061549 (denominators).

Cf. A123854 (denominators).

Cf. A161198 (triangle of coefficients for (1-x)^((-1-2*n)/2)).

Cf. A163590 (odd part of the swinging factorial).

Cf. A005187, A060818(n)= denominator(L(n)). Bisections give A061548 and A063079.

From Johannes W. Meijer, Jun 08 2009: (Start)

Cf. A001803 [(1-x)^(-3/2)], A161199 [(1-x)^(-5/2)] and A161201 [(1-x)^(-7/2)].

A161198 triangle related to the series expansions of (1-x)^((-1-2*n)/2) for all values of n.

(End)

A163590 is the odd part of the swinging factorial, A001803 at odd indices.

Inverse Moebius transform of A180403/A046161. - _Mats Granvik_, Sep 04, 2010

Cf. A123854 (denominators), A061549 (denominators). - Ralf Steiner, Apr 08 2017

Numerators of [x^n]( (1-x)^(p/2) ): A161202 (p=5), A161200 (p=3), A002596 (p=1), this sequence (p=-1), A001803 (p=-3), A161199 (p=-5), A161201 (p=-7).

STATUS

approved

editing