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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 (list; graph; refs; listen; history; text; internal format)
 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 Harvey P. Dale, Table of n, a(n) for n = 1..1000 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 Cf. A050674, A119680. Sequence in context: A156902 A050674 A164329 * A215417 A249376 A068155 Adjacent sequences: A159233 A159234 A159235 * A159237 A159238 A159239 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

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Last modified June 13 08:31 EDT 2024. Contains 373383 sequences. (Running on oeis4.)