Problem 47 - Project Euler
だめすぎる…10分はかかる…
limit <- 10^6 sieve <- logical(limit) sieve[1] <- TRUE crosslimit <- sqrt(limit) counts <- numeric(limit) for(i in 2:crosslimit){ if(!sieve[i]){ for(j in seq(i, limit, i)){ sieve[j] <- TRUE counts[j] <- counts[j] + 1 } } } i <- 1 while(1){ if(all.equal(counts[i:(i+3)], rep(4, 4))==TRUE) break i <- i+1 } i