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A351575
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Positions of primes in A351568.
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2
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4, 9, 12, 16, 18, 20, 25, 28, 44, 45, 48, 50, 52, 60, 63, 64, 68, 72, 75, 76, 80, 84, 90, 92, 99, 108, 112, 116, 117, 124, 126, 132, 140, 148, 150, 153, 156, 164, 171, 172, 175, 176, 188, 192, 198, 200, 204, 207, 208, 212, 220, 228, 234, 236, 240, 244, 260, 261, 268, 272, 275, 276, 279, 284, 288, 289, 292, 304, 306
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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f[p_, e_] := If[EvenQ[e], (p^(e + 1) - 1)/(p - 1), 1]; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[300], PrimeQ[s[#]] &] (* Amiram Eldar, Feb 25 2022 *)
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PROG
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(PARI)
A350388(n) = { my(m=1, f=factor(n)); for(k=1, #f~, if(0==(f[k, 2]%2), m *= (f[k, 1]^f[k, 2]))); (m); };
isA351575(n) = isprime(A351568(n));
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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