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 A334380 Decimal expansion of Sum_{k>=0} (-1)^k/((2*k)!!)^2. 1
 7, 6, 5, 1, 9, 7, 6, 8, 6, 5, 5, 7, 9, 6, 6, 5, 5, 1, 4, 4, 9, 7, 1, 7, 5, 2, 6, 1, 0, 2, 6, 6, 3, 2, 2, 0, 9, 0, 9, 2, 7, 4, 2, 8, 9, 7, 5, 5, 3, 2, 5, 2, 4, 1, 8, 6, 1, 5, 4, 7, 5, 4, 9, 1, 1, 9, 2, 7, 8, 9, 1, 2, 2, 1, 5, 2, 7, 2, 4, 4, 0, 1, 6, 7, 1, 8, 0, 6, 0, 0, 0, 9, 8, 9, 1, 5, 6, 3, 3, 9, 7, 4, 9, 2, 9, 2, 5, 9, 8, 2 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS This constant is transcendental. LINKS FORMULA Equals BesselJ(0,1). EXAMPLE 1/(4^0*0!^2) - 1/(4^1*1!^2) + 1/(4^2*2!^2) - 1/(4^3*3!^2) + ... = 0.765197686557966551449717526... MATHEMATICA RealDigits[BesselJ[0, 1], 10, 110] [[1]] PROG (PARI) besselj(0, 1) \\ Michel Marcus, Apr 26 2020 CROSSREFS Cf. A000165, A002454, A070910, A091681, A197036. Sequence in context: A198816 A196553 A244921 * A101464 A072558 A022963 Adjacent sequences:  A334377 A334378 A334379 * A334381 A334382 A334383 KEYWORD nonn,cons AUTHOR Ilya Gutkovskiy, Apr 25 2020 STATUS approved

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Last modified April 19 11:58 EDT 2021. Contains 343114 sequences. (Running on oeis4.)