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 A069866 Primes in which repeatedly deleting the most significant digit then the least significant digit gives a prime at every step until a single-digit prime remains. 5
 2, 3, 5, 7, 13, 17, 23, 37, 43, 47, 53, 67, 73, 83, 97, 131, 137, 173, 179, 223, 229, 271, 331, 337, 353, 359, 373, 379, 431, 479, 523, 571, 631, 653, 659, 673, 773, 823, 829, 853, 859, 929, 937, 953, 971, 1031, 1373, 1433, 1439, 1733, 2029, 2053, 2131, 2137 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Michael De Vlieger, Table of n, a(n) for n = 1..645 (Primes p <= 10^7). MATHEMATICA Select[Prime@ Range@ 400, AllTrue[FromDigits /@ Rest@ Fold[Append[#1, Delete[Last[#1], 1 - 2 Boole[EvenQ@ #2]]] &, {#}, Range[Length@ # - 1]] &@ IntegerDigits[#], PrimeQ] &] (* Michael De Vlieger, Jan 20 2018 *) CROSSREFS Cf. A024770, A033664, A069867. Sequence in context: A308711 A033664 A024785 * A125772 A233282 A001000 Adjacent sequences: A069863 A069864 A069865 * A069867 A069868 A069869 KEYWORD base,nonn AUTHOR Amarnath Murthy, Apr 21 2002 EXTENSIONS Corrected and extended by Larry Reeves (larryr(AT)acm.org), Sep 24 2002 STATUS approved

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Last modified September 21 17:35 EDT 2023. Contains 365503 sequences. (Running on oeis4.)