A341665 Primes p such that p^5 - 1 has 8 divisors.
7, 23, 83, 227, 263, 359, 479, 503, 563, 1187, 2999, 3803, 4703, 4787, 4919, 5939, 6599, 8819, 10667, 14159, 16139, 16187, 18119, 21227, 22943, 25847, 26003, 26903, 27827, 29123, 29339, 29663, 36263, 43403, 44519, 44963, 46199, 47123, 48947, 49103, 49499
Offset: 1
Keywords
Examples
p = factorization n a(n) p^5 - 1 of (p^5 - 1) - ---- -------------- --------------------- 1 7 16806 2 * 3 * 2801 2 23 6436342 2 * 11 * 292561 3 83 3939040642 2 * 41 * 48037081 4 227 602738989906 2 * 113 * 2666986681 5 263 1258284197542 2 * 131 * 4802611441 6 359 5963102065798 2 * 179 * 16656709681 7 479 25216079618398 2 * 239 * 52753304641 8 503 32198817702742 2 * 251 * 64141071121 ...
Programs
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Mathematica
Select[Range[50000], PrimeQ[#] && DivisorSigma[0, #^5 - 1] == 8 &] (* Amiram Eldar, Feb 26 2021 *)
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PARI
isok(p) = isprime(p) && (numdiv(p^5-1) == 8); \\ Michel Marcus, Feb 26 2021
Comments