A048606 Numerators of coefficients in function a(x) such that a(a(x)) = sinh(x).

1, 1, -1, 53, -23, 92713, -742031, -594673187, 329366540401, -104491760828591, 1508486324285153, 582710832978168221, -1084662989735717135537, 431265609837882130202597, 784759327625761394688977441

Offset: 0

Author

Winston C. Yang (yang(AT)math.wisc.edu)

Keywords

• frac
• sign
• nice

Comments

A recursion exists for coefficients, but is too complicated to use without a computer algebra system.

Examples

			x + x^3/12 - x^5/160 + ...
		

References

• W. C. Yang, Polynomials are essentially integer partitions, preprint, 1999
• W. C. Yang, Composition equations, preprint, 1999

Links

• W. C. Yang, Derivatives are essentially integer partitions, Discrete Math., 222 (2000), 235-245.

Crossrefs

Cf. A048603. Apart from signs, the same sequence as A048602.