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 A145426 Decimal expansion of sum_{n=0..inf} (n!/(n+2)!)^2. 4
 2, 8, 9, 8, 6, 8, 1, 3, 3, 6, 9, 6, 4, 5, 2, 8, 7, 2, 9, 4, 4, 8, 3, 0, 3, 3, 3, 2, 9, 2, 0, 5, 0, 3, 7, 8, 4, 3, 7, 8, 9, 9, 8, 0, 2, 4, 1, 3, 5, 9, 6, 8, 7, 5, 4, 7, 1, 1, 1, 6, 4, 5, 8, 7, 4, 0, 0, 1, 4, 9, 4, 0, 8, 0, 6, 4, 0, 1, 7, 4, 7, 6, 6, 7, 2, 5, 7, 8, 0, 1, 2, 3, 9 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 REFERENCES Alexander Apelblat, Tables of Integrals and Series, Harri Deutsch, (1996), 4.1.31 Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 2.19 VallĂ©e's Constant, p. 161. LINKS R. J. Mathar, Tightly circumscribed regular polygons, arXiv:1301.6293, value (A15). FORMULA Equals A002388/3-3 = sum_{n>=1} 1/A002378(n)^2 = sum_{n>=2} 1/A035287(n). EXAMPLE 0.28986813369645287294483... MAPLE evalf(1/3*Pi^2-3) ; CROSSREFS Sequence in context: A081819 A296850 A021349 * A200499 A298525 A081101 Adjacent sequences:  A145423 A145424 A145425 * A145427 A145428 A145429 KEYWORD cons,easy,nonn AUTHOR R. J. Mathar, Feb 08 2009 STATUS approved

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Last modified December 15 03:52 EST 2018. Contains 318141 sequences. (Running on oeis4.)