+ if (n<next_r)
+ return results[n/2-1];
+
+ results.reserve(n/2);
+ for (unsigned p=next_r; p<=n; p+=2) {
+ cln::cl_I c = 1; // seed for binonmial coefficients
+ cln::cl_RA b = cln::cl_RA(1-p)/2;
+ const unsigned p3 = p+3;
+ const unsigned pm = p-2;
+ unsigned i, k, p_2;
+ // test if intermediate unsigned int can be represented by immediate
+ // objects by CLN (i.e. < 2^29 for 32 Bit machines, see <cln/object.h>)
+ if (p < (1UL<<cl_value_len/2)) {
+ for (i=2, k=1, p_2=p/2; i<=pm; i+=2, ++k, --p_2) {
+ c = cln::exquo(c * ((p3-i) * p_2), (i-1)*k);
+ b = b + c*results[k-1];
+ }
+ } else {
+ for (i=2, k=1, p_2=p/2; i<=pm; i+=2, ++k, --p_2) {
+ c = cln::exquo((c * (p3-i)) * p_2, cln::cl_I(i-1)*k);
+ b = b + c*results[k-1];
+ }
+ }
+ results.push_back(-b/(p+1));
+ }
+ next_r = n+2;
+ return results[n/2-1];