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A225846 Denominator of c(n) = 2^(2*n)*(2^(2*n) - 1)/(2*n)!, a coefficient used in the expansion of tan(x) as Sum_{n>=1} c(n)*|Bernoulli(2*n)|*x^(2*n-1). 2
1, 1, 1, 5, 21, 4725, 1485, 14189175, 42567525, 516891375, 11249435925, 714620417135625, 2124921731625, 16025362854266390625, 605758715891269565625, 5703572324950265390625, 480509193164339417203125, 22913080876041525109331015625, 92765509619601316232109375 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

REFERENCES

George Boros and Victor H. Moll, Irresistible integrals, Cambridge University Press (2006), p. 63.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..250

MATHEMATICA

Table[2^(2*n)*(2^(2*n)-1)/(2*n)! // Denominator, {n, 0, 20}]

PROG

(MAGMA) [Denominator(2^(2*n)*(2^(2*n)-1)/Factorial(2*n)): n in [0..20]]; // Vincenzo Librandi, Jul 17 2013

CROSSREFS

Cf. A225845 (numerators), A000367, A002445, A002430, A036279.

Sequence in context: A193324 A220002 A156860 * A247937 A343840 A270406

Adjacent sequences:  A225843 A225844 A225845 * A225847 A225848 A225849

KEYWORD

nonn,frac,easy

AUTHOR

Jean-Fran├žois Alcover, May 17 2013

STATUS

approved

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Last modified September 27 08:39 EDT 2021. Contains 347689 sequences. (Running on oeis4.)