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A245654
Decimal expansion of the smallest positive root of the function lambda(x) = sum_{n=0..infinity} (-1)^n*x^n/(2^(n*(n-1)/2)*n!).
1
1, 4, 8, 8, 0, 7, 8, 5, 4, 5, 5, 9, 9, 7, 1, 0, 2, 9, 4, 6, 5, 6, 2, 4, 6, 0, 3, 1, 5, 8, 2, 3, 5, 7, 6, 6, 1, 8, 9, 3, 5, 1, 6, 1, 5, 2, 6, 0, 2, 9, 9, 0, 8, 0, 7, 7, 4, 9, 7, 2, 6, 8, 2, 5, 0, 1, 2, 5, 0, 5, 4, 8, 0, 6, 9, 1, 8, 5, 8, 3, 5, 7, 8, 8, 9, 9, 2, 9, 2, 5, 5, 3, 9, 5, 6, 8, 7, 4, 9, 2, 9, 7, 5
OFFSET
1,2
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.6 Otter's Tree Enumeration Constants, p. 310.
EXAMPLE
1.48807854559971029465624603158235766189351615260299080774972682501250548...
MATHEMATICA
digits = 103; lambda[x_?NumericQ] := NSum[(-1)^n*x^n/(2^(n*(n - 1)/2)*n!), {n, 0, Infinity}, WorkingPrecision -> digits + 10, Method -> "AlternatingSigns"]; xi = x /. FindRoot[lambda[x] == 0, {x, 3/2}, WorkingPrecision -> digits + 10]; RealDigits[xi, 10, digits] // First
CROSSREFS
Cf. A003024.
Sequence in context: A082210 A196282 A196332 * A135863 A176221 A021676
KEYWORD
nonn,cons
AUTHOR
STATUS
approved