9 lines
324 B
R
9 lines
324 B
R
digitsum <- function(x) sum(floor(x / 10^(0:(nchar(x) - 1))) %% 10)
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is.prime <- function(n) n == 2L || all(n %% 2L:max(2,floor(sqrt(n))) != 0)
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range_int <- 2:500
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v <- sapply(range_int, \(x) is.prime(x) && is.prime(digitsum(x)))
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cat(paste("Found",length(range_int[v]),"additive primes less than 500"))
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print(range_int[v])
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