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A100512 Numerator of Sum_{k=0..n} 1/C(2n,2k). 3
1, 2, 13, 32, 73, 647, 28211, 6080, 18181, 1542158, 2786599, 29229544, 134354573, 745984697, 80530073893, 291816652544, 274050911261, 258328905974, 18079412000719, 8574689239808, 334365081328507, 13707288497202919, 52386756782140399, 589296748617180608 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

M. Klamkin, ed., Problems in Applied Mathematics: Selections from SIAM Review, SIAM, 1990; see pp. 126-127.

LINKS

Table of n, a(n) for n=0..23.

EXAMPLE

1, 2, 13/6, 32/15, 73/35, 647/315, 28211/13860, 6080/3003, 18181/9009, 1542158/765765, 2786599/1385670, 29229544/14549535, 134354573/66927861, ... = A100512/A100513.

MATHEMATICA

Table[Sum[1/Binomial[2n, 2k], {k, 0, n}], {n, 0, 30}]//Numerator (* Harvey P. Dale, Aug 12 2016 *)

CROSSREFS

Cf. A100513, A046825.

Sequence in context: A177455 A185950 A084828 * A051474 A062708 A296293

Adjacent sequences:  A100509 A100510 A100511 * A100513 A100514 A100515

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane, Nov 25 2004

STATUS

approved

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Last modified September 28 13:24 EDT 2020. Contains 337393 sequences. (Running on oeis4.)