24/03/17 08:13:49.11 Z0Cis/1PM.net
rm(list=ls())
is.wholenumber <- function(x, tol = .Machine$double.eps^0.5){
abs(x - round(x)) < tol
}
f=function(n,m){
a=n:(n+m-1)
x=sum(a^3)^(1/3)
is.wholenumber(x)
}
f=Vectorize(f)
N=1000
n=1:N
m=1:N
z=outer(n,m,f)
colnames(z)=1:N
#z[,-1] |> sum()
#z[,-1]
#(6:69)^3 |> sum()
y=z[,-1]
a=which(y)
re=cbind(a%%N,a%/%N+2)
#re
#apply(re,1,\(x) f(x[1],x[2]))
f1=\(x){
s3=sum((x[1]:(sum(x)-1))^3)
s=s3^(1/3)
c(s,s3)
}
ans=cbind(re,t(apply(re,1,f1)))
ans[order(ans[,3]),]