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A159236
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Primes that remain prime when a 0 is inserted between every pair of adjacent digits.
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20
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11, 13, 17, 19, 37, 41, 53, 59, 61, 67, 71, 79, 89, 97, 107, 109, 113, 131, 151, 167, 179, 193, 199, 211, 257, 277, 293, 313, 337, 359, 373, 383, 389, 409, 457, 479, 577, 599, 613, 617, 659, 661, 673, 691, 701, 709, 727, 739, 751, 757, 827, 829, 839, 863, 883
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OFFSET
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1,1
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COMMENTS
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See A119680 for the primes obtained by inserting a 0 between each pair of adjacent digits. - Rémy Sigrist, Oct 08 2017
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LINKS
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EXAMPLE
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409 is prime, and so is 40009 ( 4(0)0(0)9 ). Hence 409 is in the sequence.
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MAPLE
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Lton := proc(L) add( op(i, L)*10^(i-1), i=1..nops(L)) ; end: pad0 := proc(n) dgs := convert(n, base, 10) ; L := [op(1, dgs)] ; for i from 2 to nops(dgs) do L := [op(L), 0, op(i, dgs)] ; od: Lton(L) ; end: for i from 5 to 400 do p := ithprime(i) ; if isprime( pad0(p) ) then printf("%d, ", p) ; fi; od: # R. J. Mathar, Apr 07 2009
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MATHEMATICA
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Select[Prime[Range[5, 200]], PrimeQ[FromDigits[Riffle[ IntegerDigits[ #], 0]]]&] (* Harvey P. Dale, Feb 19 2015 *)
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PROG
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(Python)
from sympy import isprime
def ok(n):
return n > 10 and isprime(n) and isprime(int("0".join(list(str(n)))))
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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