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A159236
Primes that remain prime when a 0 is inserted between every pair of adjacent digits.
20
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
OFFSET
1,1
COMMENTS
Prime terms in A050674.
See A119680 for the primes obtained by inserting a 0 between each pair of adjacent digits. - Rémy Sigrist, Oct 08 2017
LINKS
EXAMPLE
409 is prime, and so is 40009 ( 4(0)0(0)9 ). Hence 409 is in the sequence.
MAPLE
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
MATHEMATICA
Select[Prime[Range[5, 200]], PrimeQ[FromDigits[Riffle[ IntegerDigits[ #], 0]]]&] (* Harvey P. Dale, Feb 19 2015 *)
PROG
(Python)
from sympy import isprime
def ok(n):
return n > 10 and isprime(n) and isprime(int("0".join(list(str(n)))))
print([k for k in range(900) if ok(k)]) # Michael S. Branicky, Jul 11 2022
CROSSREFS
Sequence in context: A156902 A050674 A164329 * A215417 A249376 A068155
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, Apr 06 2009
EXTENSIONS
Edited by N. J. A. Sloane, Apr 07 2009
Extended by R. J. Mathar, Apr 07 2009
STATUS
approved