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 A242562 Primes p such that 1000p+1, 1000p+3, 1000p+7 and 1000p+9 are prime. 2
 13, 1447, 5527, 28201, 36217, 75079, 81157, 95911, 187423, 188677, 202327, 210643, 248077, 263323, 282589, 283267, 423043, 466897, 472597, 478189, 478603, 631273, 640261, 695749, 730111, 736279, 806929, 808021, 917641, 964303, 1018177, 1026547, 1064263, 1108489, 1150861 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..35. EXAMPLE 130001, 130003, 130007 and 130009 are all prime. Thus 13 is a member of this sequence. PROG (Python) import sympy from sympy import isprime from sympy import prime {print(prime(n)) for n in range(1, 10**5) if isprime(1000*prime(n)+1) and isprime(1000*prime(n)+3) and isprime(1000*prime(n)+7) and isprime(1000*prime(n)+9)} (PARI) for(n=1, 10^5, s=prime(n); if(ispseudoprime(1000*s+1) && ispseudoprime(1000*s+3) && ispseudoprime(1000*s+7) && ispseudoprime(1000*s+9), print(s))); CROSSREFS Cf. A236042, A067267. Sequence in context: A197097 A353030 A064962 * A201357 A220551 A185073 Adjacent sequences: A242559 A242560 A242561 * A242563 A242564 A242565 KEYWORD nonn AUTHOR Derek Orr, May 17 2014 STATUS approved

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Last modified June 12 23:19 EDT 2024. Contains 373360 sequences. (Running on oeis4.)