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A177819
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Numbers k such that k^3 divides 19^(k^2) + 1.
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9
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1, 5, 55, 1265, 11255, 59455, 123805, 395755, 635255, 874115, 1028555, 1456015, 2847515, 3201715, 3841805, 4353305, 6655055, 6987805, 13443155, 16825765, 23656765, 36370015, 41083405, 66919765, 68432705, 100126015, 123012395
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OFFSET
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1,2
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COMMENTS
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5 divides a(n) for n > 1.
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LINKS
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MATHEMATICA
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Select[Range[123020000], PowerMod[19, #^2, #^3]==#^3-1&] (* Harvey P. Dale, May 20 2021 *)
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CROSSREFS
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Cf. A127263 (k^3 divides 2^(k^2) + 1).
Cf. A128677 (least k > p such that (k*p)^3 divides (p-1)^(k*p)^2+1, where p = prime(n) > 2).
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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