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A334378 Decimal expansion of Sum_{k>=0} 1/((2*k+1)!)^2. 2
1, 0, 2, 7, 8, 4, 7, 2, 6, 1, 5, 9, 7, 4, 1, 5, 7, 9, 9, 6, 9, 2, 6, 8, 8, 4, 9, 3, 0, 8, 0, 7, 9, 2, 3, 6, 3, 7, 3, 0, 3, 4, 3, 3, 1, 0, 2, 8, 3, 4, 2, 5, 7, 2, 5, 4, 7, 1, 2, 4, 5, 0, 2, 2, 8, 2, 6, 7, 2, 5, 6, 9, 2, 7, 3, 2, 3, 3, 2, 8, 1, 8, 8, 5, 7, 3, 5, 2, 7, 8, 8, 3, 5, 1, 5, 2, 8, 2, 6, 6, 4, 6, 7, 6, 7, 9, 2, 3, 7, 8 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..110.

Index entries for sequences related to Bessel functions or polynomials

FORMULA

Equals (BesselI(0,2) - BesselJ(0,2))/2.

EXAMPLE

1/1!^2 + 1/3!^2 + 1/5!^2 + 1/7!^2 + ... = 1.027847261597415799692...

MATHEMATICA

RealDigits[(BesselI[0, 2] - BesselJ[0, 2])/2, 10, 110] [[1]]

PROG

(PARI) suminf(k=0, 1/((2*k+1)!)^2) \\ Michel Marcus, Apr 26 2020

(PARI) (besseli(0, 2) - besselj(0, 2))/2 \\ Michel Marcus, Apr 26 2020

CROSSREFS

Cf. A009445, A049469, A070910, A073742, A091681, A197036, A334379.

Sequence in context: A316252 A202355 A202357 * A329406 A019731 A021363

Adjacent sequences:  A334375 A334376 A334377 * A334379 A334380 A334381

KEYWORD

nonn,cons

AUTHOR

Ilya Gutkovskiy, Apr 25 2020

STATUS

approved

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Last modified May 14 22:40 EDT 2021. Contains 343909 sequences. (Running on oeis4.)