RosettaCodeData/Task/Factorial-primes/R/factorial-primes.r
2025-08-11 18:05:26 -07:00

29 lines
625 B
R

library(gmp)
print_20digits <- function(z){
s <- as.character(z)
if(nchar(s)>40){
paste0(substring(s, 1, 20), "...", substring(s, nchar(s)-19, nchar(s)))
}
else return(s)
}
count <- 0
n <- 1
while(count<33){
plus <- factorialZ(n)+1
minus <- factorialZ(n)-1
if(isprime(plus)!=0){
cat(n, "!+1 = ", print_20digits(plus),
" (", nchar(as.character(plus)), " digits)",
"\n", sep="")
count <- count+1
}
if(isprime(minus)!=0){
cat(n, "!-1 = ", print_20digits(minus),
" (", nchar(as.character(minus)), " digits)",
"\n", sep="")
count <- count+1
}
n <- n+1
}