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A278585
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Numbers k such that k+1 is a prime, k+2 is twice a prime, k+3 is three times a prime, and k+4 is four times a prime.
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4
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12720, 16920, 19440, 24480, 49680, 61560, 104160, 229320, 255360, 259680, 266400, 291720, 298200, 311040, 331920, 419400, 423480, 436800, 446880, 471240, 525240, 532800, 539400, 581520, 600600, 663600, 704160, 709920, 783720, 867000, 904800, 908040, 918360
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Select[Range[920000], AllTrue[{#+1, (#+2)/2, (#+3)/3, (#+4)/4}, PrimeQ]&] (* Harvey P. Dale, Aug 08 2021 *)
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PROG
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(Python)
from sympy import prime, isprime
A278585_list = [4*q-4 for q in (prime(i) for i in range(1, 10000)) if isprime(4*q-3) and isprime(2*q-1) and (not (4*q-1) % 3) and isprime((4*q-1)//3)] # Chai Wah Wu, Nov 30 2016
(PARI) is(k)=k%120==0 && isprime(k+1) && isprime(k/2+1) && isprime(k/3+1) && isprime(k/4+1) \\ Charles R Greathouse IV, Dec 03 2016
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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