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A122143 Decimal expansion of Sum_{k >= 1} cos(k)/k^2. 3
3, 2, 4, 1, 3, 7, 7, 4, 0, 0, 5, 3, 3, 2, 9, 8, 1, 7, 2, 4, 1, 0, 9, 3, 4, 7, 5, 0, 0, 6, 2, 7, 3, 7, 4, 7, 1, 2, 0, 3, 6, 5, 2, 0, 1, 5, 1, 9, 2, 4, 5, 5, 2, 7, 2, 4, 8, 0, 8, 5, 9, 3, 3, 2, 1, 6, 0, 9, 9, 2, 6, 7, 2, 6, 0, 0, 9, 6, 3, 7, 4, 5, 1, 9, 6, 1, 1, 4, 8, 7, 9, 4, 8, 7, 0, 0, 1, 7, 1, 3, 1, 2, 9, 3 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Also, decimal expansion of the real part of Sum_{k>=1} e^(i*k)/k^2. [Bruno Berselli, Mar 24 2013]
LINKS
FORMULA
Equals (2*Pi*(Pi-3)+3)/12.
EXAMPLE
0.324137740053329817241093475006273747120365201519245527248085933216...
MATHEMATICA
Print[x=FullSimplify[Sum[Cos[n]/n^2, {n, Infinity}]]]; RealDigits[N[x, 110]][[1]]
PROG
(PARI) (2*Pi*(Pi-3)+3)/12 \\ Jianing Song, Nov 09 2019
CROSSREFS
Cf. A096418 (decimal expansion of Sum_{k >= 1} sin(k)/k^2).
Sequence in context: A123359 A121885 A187760 * A144868 A134029 A117623
KEYWORD
nonn,cons
AUTHOR
T. D. Noe, Aug 28 2006
STATUS
approved

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Last modified June 21 04:30 EDT 2024. Contains 373540 sequences. (Running on oeis4.)