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A287550 Initial prime in set of 4 consecutive primes in arithmetic progression with difference 72.

%I A287550 #16 Jun 03 2017 12:20:45
%S A287550 491525857,1470227987,2834347387,4314407477,4766711387,6401372837,
%T A287550 6871241197,8971400797,10168905497,11776429517,11871902557,
%U A287550 14538547967,14925896087,15218517367,15646776877,15875854927,17310026197,17942416307,18347931587,19241492057,19379888947
%N A287550 Initial prime in set of 4 consecutive primes in arithmetic progression with difference 72.
%C A287550 a(1)=491525857=A052239(12).
%H A287550 Chai Wah Wu, <a href="/A287550/b287550.txt">Table of n, a(n) for n = 1..100</a>
%o A287550 (Python)
%o A287550 from gmpy2 import is_prime, next_prime
%o A287550 A287550_list, p = [], 2
%o A287550 q, r, s = p+72, p+144, p+216
%o A287550 while s <= 10**10:
%o A287550     np = next_prime(p)
%o A287550     if np == q and is_prime(r) and is_prime(s) and next_prime(q) == r and next_prime(r) == s:
%o A287550         A287550_list.append(p)
%o A287550     p, q, r, s = np, np+72, np+144, np+216 # _Chai Wah Wu_, Jun 03 2017
%Y A287550 Analogous sequences [with common difference in square brackets]: A033451 [6], A033447 [12], A033448 [18], A052242 [24], A052243 [30], A058252 [36], A058323 [42], A067388 [48], A259224 [54], A210683 [60]. Cf. A052239.
%K A287550 nonn
%O A287550 1,1
%A A287550 _Zak Seidov_, May 26 2017
%E A287550 a(8)-a(21) from _Chai Wah Wu_, Jun 03 2017