My logic was similar, in R: library(dplyr) combos <- expand.grid(x = 1:99, y = 1:99) |> filter(x <= y) |> # Remove dupes mutate(sum = x + y, pro

My logic was similar, in R: library(dplyr) combos <- expand.grid(x = 1:99, y = 1:99) |> filter(x <= y) |> # Remove dupes mutate(sum = x + y, prod = x * y) find_singletons <- function(col = c("sum", "prod")) { singletons <- combos %>% group_by(!!sym(col)) %>% tally() %>% filter(n == 1) which(combos[[col]] %in% singletons[[col]]) } for (i in 1:7) { # Peter: I don't know the numbers. combos <- combos[-find_singletons("prod"),] # Sandy: I don't know the numbers. combos <- combos[-find_singletons("sum"),] } # Peter: I know the numbers. combos[find_singletons("prod"),]