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A256621 Primes p such that the decimal expansion of p remains prime under three iterations of base-10 to base-2 conversion. 5
3893257, 9023533, 11005327, 11659009, 18747809, 21855233, 25183007, 34074379, 54298687, 58562951, 60496981, 89891273, 94277683, 96602887, 102276859, 115555927, 117578429, 122191543, 125115709, 132837283, 138169991, 139442753, 168852077, 183879649, 184904831 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
Sebastian Petzelberger, Table of n, a(n) for n = 1..10000
Carlos Rivera, Puzzle 280. 3893257, The Prime Puzzles and Problems Connection.
EXAMPLE
The 3 iterations: 3893257 --> 1110110110100000001001 --> ... --> ... are prime.
PROG
(PARI) isok(n, nb=3) = {for (k=1, nb, b = binary(n); d = eval(subst(Pol(b), x, 10)); if (! isprime(d), return (0)); n = d; ); return (1); } \\ Michel Marcus, Apr 08 2015
CROSSREFS
Sequence in context: A247088 A204319 A251439 * A213159 A253406 A251071
KEYWORD
nonn,base
AUTHOR
STATUS
approved

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Last modified March 29 10:22 EDT 2024. Contains 371268 sequences. (Running on oeis4.)