# project euler 37
# many of the same primality checks, so memo
# n ? is_prime(n)
p ← memo(=1⧻°/×)

# by picking sufficiently large n (n > ~800000),
# all such primes will be found.
n ← 800000
▽⊸≡p+8⇡n # find primes below n, skipping first 7
▽⊸≡(
  # keep those that satisfy
  ⊃⍜⇌⧅(⋕⇌)⧅⋕ °⋕ # (1) prefixes; and (2) suffixes
  ↧∩(/↧≡p)      # are all prime
)
/+ # sum primes

# online pad
# https://www.uiua.org/pad?src=0_17_0-dev_2__IyBwcm9qZWN0IGV1bGVyIDM3CiMgbWFueSBvZiB0aGUgc2FtZSBwcmltYWxpdHkgY2hlY2tzLCBzbyBtZW1vCiMgbiA_IGlzX3ByaW1lKG4pCnAg4oaQIG1lbW8oPTHip7vCsC_DlykKCm4g4oaQIDEwMDAK4pa94oq44omhcCs44oehbiAjIGZpbmQgcHJpbWVzIGJlbG93IG4sIHNraXBwaW5nIGZpcnN0IDcK4pa94oq44omhKAogICMga2VlcCB0aG9zZSB0aGF0IHNhdGlzZnkKICDiioPijZzih4zip4Uo4ouV4oeMKeKnheKLlSDCsOKLlSAjICgxKSBwcmVmaXhlczsgYW5kICgyKSBzdWZmaXhlcwogIOKGp-KIqSgv4oan4omhcCkgICAgICAjIGFyZSBhbGwgcHJpbWUKKQovK-KfnOKnuyAjIHN1bSBhbmQgY291bnQK