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A050990
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2-Knödel numbers.
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17
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4, 6, 8, 10, 12, 14, 22, 24, 26, 30, 34, 38, 46, 56, 58, 62, 74, 82, 86, 94, 106, 118, 122, 132, 134, 142, 146, 158, 166, 178, 182, 194, 202, 206, 214, 218, 226, 254, 262, 274, 278, 298, 302, 314, 326, 334, 346, 358, 362, 382, 386, 394, 398, 422, 446, 454, 458
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OFFSET
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1,1
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COMMENTS
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Numbers k > 2 such that A002322(k) divides k-2. Contains all doubled primes and all doubled Carmichael numbers. - Thomas Ordowski, Apr 23 2017
Problem: are there infinitely many 2-Knodel numbers divisible by 4? - Thomas Ordowski, Jun 21 2017
Named after the Austrian mathematician and computer scientist Walter Knödel (1926-2018). - Amiram Eldar, Jun 08 2021
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LINKS
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MATHEMATICA
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Select[Range[4, 460, 2], Divisible[# - 2, CarmichaelLambda@ #] &] (* Michael De Vlieger, Apr 24 2017 *)
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PROG
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(PARI) a002322(n) = lcm(znstar(n)[2]);
forstep(n=4, 500, 2, if((n - 2)%a002322(n)==0, print1(n, ", "))) \\ Indranil Ghosh, Jun 22 2017
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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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