OFFSET
1,2
COMMENTS
a(n)>=n+3 for n>=8 (Butcher 1985).
LINKS
J. C. Butcher, On the attainable Order of Runge-Kutta methods, Math. Comp. 19 (1965) 408-417.
J. C. Butcher, The non-existence of ten stage eighth order explicit Runge-Kutta methods, BIT 25 (1985) 521-540.
A. R. Curtis, An eighth order Runge-Kutta process with eleven function evaluations per step, Numer. Math. 16 (1970) 268-277.
MathOverflow, What is the minimum number of stages s required for a Runge-Kutta type numerical method of given order p?, 2019.
Wikipedia, Runge-Kutta methods.
FORMULA
a(n) = min{k; A187103(k)=n}.
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
Pontus von Brömssen, Mar 04 2011
STATUS
approved