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A245878
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Primes p such that p - d and p + d are also primes, where d is the smallest nonzero digit of p.
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1
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67, 607, 6977, 68897, 69067, 69997, 79867, 80677, 88867, 97967, 609607, 660067, 669667, 676987, 678767, 697687, 707677, 766867, 777677, 786697, 866087, 879667, 880667, 886987, 899687, 906707, 909767, 966997, 990967, 6069977, 6096907, 6097997, 6678877
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OFFSET
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1,1
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COMMENTS
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The smallest nonzero digit of a(n) is 6, and the least significant digit of a(n) is 7.
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LINKS
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EXAMPLE
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The prime 607 is in the sequence because 607 - 6 = 601 and 607 + 6 = 613 are both primes.
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MATHEMATICA
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pdQ[p_]:=Module[{c=Min[DeleteCases[IntegerDigits[p], 0]]}, AllTrue[p+{c, -c}, PrimeQ]]; Select[Prime[Range[460000]], pdQ] (* Harvey P. Dale, Feb 26 2023 *)
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PROG
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(PARI) s=[]; forprime(p=2, 7000000, v=vecsort(digits(p), , 8); d=v[1+!v[1]]; if(isprime(p-d) && isprime(p+d), s=concat(s, p))); s
(Python)
import sympy
from sympy import isprime
from sympy import prime
for n in range(1, 10**6):
..s=prime(n)
..lst = []
..for i in str(s):
....if i != '0':
......lst.append(int(i))
..if isprime(s+min(lst)) and isprime(s-min(lst)):
....print(s, end=', ')
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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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STATUS
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approved
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