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A216498 Primes p with property that there exists a number d>0 such that numbers p-k*d, k=1...5, are five primes. 7
157, 257, 311, 353, 463, 509, 691, 757, 823, 839, 881, 907, 941, 953, 1063, 1097, 1223, 1229, 1249, 1297, 1301, 1307, 1439, 1459, 1531, 1583, 1669, 1723, 1777, 1879, 1907, 1913, 1931, 2027, 2087, 2089, 2141, 2143, 2179, 2207, 2293, 2351, 2371, 2377, 2399, 2411 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Conjecture: only 9198 primes are not in the sequence: 2, 3, ..., 2521081.
LINKS
EXAMPLE
157 is in the sequence because with d=30: 127, 97, 67, 37, 7 are all primes.
MATHEMATICA
prms = 5; fQ[p_] := Module[{d = 1}, While[prms*d < p && Union[PrimeQ[p - Range[prms]*d]] != {True}, d++]; prms*d < p]; Select[Prime[Range[2, PrimePi[2411]]], fQ] (* T. D. Noe, Sep 08 2012 *)
PROG
(PARI) is(n)=my(t); forprime(p=2, n-16, if((n-p)%5==0 && isprime((t=(n-p)/5)+p) && isprime(2*t+p) && isprime(3*t+p) && isprime(4*t+p) && isprime(n), return(1))); 0 \\ Charles R Greathouse IV, Sep 10 2014
CROSSREFS
Sequence in context: A142231 A020356 A142367 * A275317 A303094 A001837
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Sep 08 2012
STATUS
approved

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Last modified March 30 02:37 EDT 2024. Contains 371289 sequences. (Running on oeis4.)