A253940
Primes p such that (p^2 + 5)/6, (p^4 + 5)/6, and (p^8 + 5)/6 are prime.
Original entry on oeis.org
39367, 52163, 67103, 79631, 100981, 280547, 318457, 530711, 605123, 815401, 833923, 834947, 928871, 1313857, 1734067, 1750069, 1800973, 2163979, 2427137, 2598119, 2611027, 2754991, 2764187, 2836259, 3040757, 3101309, 3118697, 3465953, 3646693, 4014809
Offset: 1
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[p: p in PrimesUpTo(10^7) | IsPrime((p^2+5) div 6) and IsPrime((p^4+5) div 6) and IsPrime((p^8+5) div 6)]; // Vincenzo Librandi, Jan 21 2015
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Select[Prime[Range[10^6]], PrimeQ[(#^2 + 5) / 6] &&PrimeQ[(#^4 + 5) / 6] &&PrimeQ[(#^8 + 5) / 6] &] (* Vincenzo Librandi, Jan 21 2015 *)
Select[Prime[Range[300000]],AllTrue[({#^2,#^4,#^8}+5)/6,PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 15 2021 *)
A253941
Primes p such that (p^2 + 5)/6, (p^4 + 5)/6, (p^6 + 5)/6, (p^8 + 5)/6 and (p^10 + 5)/6 are all prime.
Original entry on oeis.org
184279409, 619338131, 913749803, 1057351301, 1507289869, 1600204213, 2845213937, 4725908767, 4760956439, 5374709801, 5518707641, 8724256757, 9044067313, 9387396269, 10992352517, 11937043567, 13493126359, 13593105793, 17891702891, 17897035213, 17954907767, 19690938161, 20227580927, 20922685813, 21313027583, 21717176851
Offset: 1
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lista(nn) = forprime(p=5, nn, if(ispseudoprime((p^2 + 5)/6) && ispseudoprime((p^4 + 5)/6) && ispseudoprime((p^6 + 5)/6) && ispseudoprime((p^8 + 5)/6) && ispseudoprime((p^10 + 5)/6), print1(p, ", "))); \\ Jinyuan Wang, Mar 01 2020
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from gmpy2 import is_prime, t_divmod
A253941_list = []
for p in range(1,10**6,2):
if is_prime(p):
p2, x = p**2, 1
for i in range(5):
x *= p2
q, r = t_divmod(x+5,6)
if r or not is_prime(q):
break
else:
A253941_list.append(p) # Chai Wah Wu, Jan 22 2015
A253939
Primes p such that (p^2 + 5)/6, (p^4 + 5)/6 and (p^6 + 5)/6 are prime.
Original entry on oeis.org
7309, 45361, 67103, 97777, 128521, 149381, 374669, 543313, 656459, 872747, 940913, 1110817, 1219877, 1288603, 1324567, 1599319, 1629809, 2006677, 2129527, 2495501, 2544121, 2735839, 2763053, 2786363, 2856167, 3145661, 3428839, 3585149, 4063877, 4115971
Offset: 1
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[p: p in PrimesUpTo(10^7) | IsPrime((p^2+5) div 6) and IsPrime((p^4+5) div 6) and IsPrime((p^6+5) div 6)]; // Vincenzo Librandi, Jan 21 2015
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Select[Prime[Range[10^7]], PrimeQ[(#^2 + 5) / 6] &&PrimeQ[(#^4 + 5) / 6] &&PrimeQ[(#^6 + 5) / 6] &] (* Vincenzo Librandi, Jan 21 2015 *)
Select[Prime[Range[3*10^5]],AllTrue[(#^{2,4,6}+5)/6,PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 10 2016 *)
Showing 1-3 of 3 results.
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