A245651 Decimal expansion of eta/xi = A086318/A086317, a coefficient associated with the asymptotics of the number of weakly binary trees.

3, 1, 8, 7, 7, 6, 6, 2, 5, 9, 2, 5, 0, 2, 9, 6, 7, 5, 4, 8, 0, 0, 8, 1, 7, 6, 9, 7, 7, 8, 0, 1, 3, 1, 8, 1, 9, 7, 2, 1, 2, 4, 1, 8, 6, 7, 8, 7, 8, 7, 0, 1, 7, 0, 1, 9, 7, 5, 4, 9, 6, 8, 1, 7, 8, 9, 5, 7, 3, 2, 3, 4, 2, 6, 0, 2, 2, 9, 9, 0, 0, 6, 4, 0, 9, 1

Offset: 0

Author

Jean-François Alcover, Jul 28 2014

Keywords

• nonn
• cons

Examples

			0.31877662592502967548008176977801318197212418678787017019754968178957323426...
		

References

• Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, Section 5.6 Otter's Tree Enumeration Constants, p. 297.

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1000
• Nils Berglund, Christian Kuehn, Model Spaces of Regularity Structures for Space-Fractional SPDEs, Journal of Statistical Physics, Springer Verlag, 2017, 168 (2), pp.331-368; HAL Id : hal-01432157.
• Eric Weisstein's MathWorld, Weakly binary tree

Crossrefs

Cf. A086317, A086318.

Programs

Mathematica

digits = 103; Clear[c, k]; c[0] = 2; c[n_] := c[n] = c[n-1]^2 + 2; k[n_] := k[n] = (Sqrt[c[n]^2^(-n)]*Sqrt[3 + Sum[1/Product[c[j], {j, 1, k}], {k, 1, n}]])/(c[n]^2^(-n)*(2*Sqrt[Pi])); k[5]; k[n = 10]; While[RealDigits[k[n], 10, digits] != RealDigits[k[n-5], 10, digits], n = n+5]; RealDigits[k[n], 10, digits] // First