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A258879
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Numbers n such that n is the average of four consecutive primes n-7, n-1, n+1 and n+7.
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1
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30, 60, 270, 570, 600, 1230, 1290, 1620, 2340, 2550, 3540, 4020, 4650, 5850, 6270, 6360, 6570, 10860, 11490, 14550, 15270, 17490, 19080, 19380, 19470, 23670, 26730, 29130, 32370, 34260, 41610, 48480, 49200, 49530, 51420, 51480
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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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FORMULA
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EXAMPLE
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For n=30: 23, 29, 31, 37 are consecutive primes (n-7=23, n-1=29, n+1=31, n+7=37).
For n=60: 53, 59, 61, 67 are consecutive primes (n-7=53, n-1=59, n+1=61, n+7=67).
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MATHEMATICA
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Select[ 5 Range@ 11000, PrimeQ[# - 7] && PrimeQ[# - 1] && PrimeQ[# + 1] && PrimeQ[# + 7] &] (* Robert G. Wilson v, Jun 28 2015 *)
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PROG
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(Python)
from sympy import isprime, prevprime, nextprime
for i in range(0, 10001, 2):
..if isprime(i-1) and isprime(i+1):
....if prevprime(i-1) == i-7 and nextprime(i+1) == i+7 : print (i, end=', ')
(Magma) [n: n in [13..2*10^5] | IsPrime(n-7) and IsPrime(n-1) and IsPrime(n+1) and IsPrime(n+7)]; // Vincenzo Librandi Jul 16 2015
(PARI) main(size)={my(v=vector(size), i, t=8); for(i=1, size, while(1, if(isprime(t-7)&&isprime(t-1)&&isprime(t+1)&&isprime(t+7), v[i]=t; break, t++)); t++); return(v); } /* Anders Hellström, Jul 17 2015 */
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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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