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A062779 a(n) = 2*n*(2*n)!. 1
0, 4, 96, 4320, 322560, 36288000, 5748019200, 1220496076800, 334764638208000, 115242726703104000, 48658040163532800000, 24728016011107368960000, 14890761641597746544640000, 10485577989291746525184000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..13.

Wikipedia, Cosine integral.

Wikipedia, Hyperbolic cosine integral.

FORMULA

From Amiram Eldar, Feb 14 2021: (Start)

a(n) = A001563(2*n) = 2*n*A010050(n).

Sum_{n>=1} 1/a(n) = Chi(1) - gamma = A099284 - A001620, where Chi(x) is the hyperbolic cosine integral

Sum_{n>=1} (-1)^(n+1)/a(n) = gamma - Ci(1) = A001620 - A099282, where Ci(x) is the cosine integral. (End)

MATHEMATICA

a[n_] := 2*n*(2*n)!; Array[a, 14, 0] (* Amiram Eldar, Feb 14 2021 *)

PROG

(PARI) for(n=0, 22, print((2*n)*(2*n)!))

CROSSREFS

Cf. A001563, A001620, A010050, A099282, A099284.

Sequence in context: A267907 A221148 A317664 * A077155 A013042 A190196

Adjacent sequences: A062776 A062777 A062778 * A062780 A062781 A062782

KEYWORD

easy,nonn

AUTHOR

Jason Earls, Jul 18 2001

STATUS

approved

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Last modified December 9 10:59 EST 2022. Contains 358700 sequences. (Running on oeis4.)