def nat64
import bend-collections@1.0.0.0/src/math/random/rand.bend as Randimport Base
import bend-collections@1.0.0.0/src/math/u64.bend as W
197# the 64-bit word of n < 2^64
198def nat64(+n: Nat) -> W.U64:
199 W.U64{w_go(4n, n), w_go(4n, skip(4n, n))}