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A365326
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a(n) is the smallest positive number k such that k^2 - 1 and k^2 + 1 each have exactly n distinct prime divisors.
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0
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2, 5, 13, 83, 463, 4217, 169333, 2273237, 23239523, 512974197, 5572561567
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OFFSET
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1,1
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LINKS
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FORMULA
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PROG
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(PARI) isok(k, n) = (omega(k^2-1)==n) && (omega(k^2+1)==n);
a(n) = my(k=2); while (!isok(k, n), k++); k; \\ Michel Marcus, Sep 03 2023
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CROSSREFS
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Cf. A088075 (with k instead of k^2).
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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