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A397226
Decimal expansion of Sum_{k>=1} (-1)^(k+1) * AH(k)/k^4, where AH(k) = A058313(k)/A058312(k) is the k-th alternating harmonic (or skew-harmonic) number.
3
9, 7, 7, 7, 8, 5, 1, 4, 7, 7, 4, 2, 5, 0, 5, 3, 9, 3, 2, 7, 9, 5, 9, 7, 2, 1, 0, 6, 2, 4, 9, 1, 5, 2, 8, 3, 7, 5, 6, 7, 3, 1, 5, 3, 0, 9, 3, 6, 3, 1, 5, 8, 6, 9, 6, 1, 1, 4, 9, 7, 8, 1, 3, 7, 2, 8, 0, 2, 6, 7, 8, 8, 0, 3, 5, 9, 0, 7, 5, 0, 7, 7, 5, 7, 5, 0, 3, 8, 0, 9, 4, 2, 3, 2, 2, 7, 1, 2, 5, 9, 8, 0, 2, 6, 3
OFFSET
0,1
LINKS
Ali Shadhar Olaikhan, An Introduction to the Harmonic Series and Logarithmic Integrals, 2nd ed., 2023, section 4.1, p. 261.
Cornel Ioan Vălean, More (Almost) Impossible Integrals, Sums, and Series, Springer Cham, 2023. See section 4.22, p. 427.
FORMULA
Equals 15*log(2)*zeta(4)/8 + 3*zeta(2)*zeta(3)/4 - 59*zeta(5)/32.
EXAMPLE
0.977785147742505393279597210624915283756731530936315...
MATHEMATICA
RealDigits[15*Log[2]*Zeta[4]/8 + 3*Zeta[2]*Zeta[3]/4 - 59*Zeta[5]/32, 10, 120][[1]]
PROG
(PARI) 15*log(2)*zeta(4)/8 + 3*zeta(2)*zeta(3)/4 - 59*zeta(5)/32
CROSSREFS
Sum_{k>=1} (-1)^(k+1) * AH(k)/k^m: A369884 (m=1), A397225 (m=2), this constant (m=4), A397227 (m=6), A397228 (m=8).
Sequence in context: A183699 A203079 A232128 * A336081 A086278 A081855
KEYWORD
nonn,cons
AUTHOR
Amiram Eldar, Jun 19 2026
STATUS
approved