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, 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.

Links

Table of n, a(n) for n=1..103.

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

Adjacent sequences: A245651 A245652 A245653 * A245655 A245656 A245657

Keyword

nonn,cons

Author

Jean-François Alcover, Jul 28 2014

Status

approved