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 A240696 Prime numbers n such that replacing each digit d in the decimal expansion of n with its 9's complement produces a prime. 0
 2, 7, 97, 997, 99999999999999997 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(n) = {2} union {primes of the form 10^n - 3} = {2} union {A093172}. Primes p such that A061601(p) is also prime. The next term has 140 digits. LINKS EXAMPLE 997 is in the sequence because 997 becomes (002) = 2, which is prime. MATHEMATICA lst={}; f[n_]:=Block[{a=IntegerDigits[Prime[n]], b="", k=1, l}, l=Length[a]; While[k

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Last modified July 25 18:32 EDT 2021. Contains 346291 sequences. (Running on oeis4.)