A090872
a(n) is the smallest number m greater than 1 such that m^(2^k)+1 for k=0,1,...,n are primes.
Original entry on oeis.org
2, 2, 2, 2, 2, 7072833120, 2072005925466, 240164550712338756
Offset: 0
a(5)=7072833120 because 7072833120^2^k+1 for k=0,1,2,3,4,5 are primes.
A070694
Numbers b such that b+1, b^2+1, b^4+1, b^8+1 and b^16+1 are primes.
Original entry on oeis.org
1, 2, 337536, 585106, 602056, 2071960, 11861410, 20706120, 54020170, 72696726, 87584646, 89445636, 95895930, 98583340, 98595070, 112204200, 205739220, 279448296, 292582836, 337969690, 349672456, 432972780, 437874186, 474186576, 479631880, 483333426, 621777466, 643697776
Offset: 1
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Do[ If[ PrimeQ[n + 1] && PrimeQ[n^2 + 1] && PrimeQ[n^4 + 1] && PrimeQ[n^8 + 1] && PrimeQ[n^16 + 1], Print[n]], {n, 1, 10^7}]
Select[Range[21*10^5],AllTrue[#^2^Range[0,4]+1,PrimeQ]&] (* The program generates the first six terms of the sequence. *) (* Harvey P. Dale, Jun 02 2024 *)
A335805
Numbers b such that b^(2^i) + 1 is prime for i = 0...6.
Original entry on oeis.org
1, 2072005925466, 5082584069416, 12698082064890, 29990491969260, 46636691707050, 65081025897426, 83689703895606, 83953213480290, 105003537341346, 105699143244090, 107581715369910, 111370557491826, 111587899569066, 128282713771996, 133103004825210
Offset: 1
A337364
Numbers b such that b^(2^i) + 1 is prime for i = 0...7.
Original entry on oeis.org
1, 240164550712338756, 3686834112771042790, 6470860179642426900, 7529068955648085700, 10300630358100537120, 16776829808789151280, 17622040391833711780, 19344979062504927000, 23949099004395080026, 25348938242408650240, 30262840543567048476, 35628481193915651646
Offset: 1
Showing 1-4 of 4 results.
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