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A278021
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Numbers n such that n - lambda(n) is prime, where lambda = A002322.
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2
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4, 9, 15, 25, 33, 35, 49, 65, 69, 77, 87, 91, 95, 115, 119, 121, 123, 143, 159, 169, 185, 187, 215, 221, 247, 249, 255, 259, 267, 287, 289, 295, 299, 319, 323, 329, 339, 341, 361, 365, 377, 393, 395, 407, 413, 415, 427, 437, 455, 473, 485, 511, 515, 519
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OFFSET
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1,1
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COMMENTS
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All terms are composite.
4 is the only even term.
For odd primes p, 3*p is a term iff p is in A005384.
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LINKS
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FORMULA
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EXAMPLE
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25-lambda(25) = 25-20 = 5 is prime so 25 is in the sequence.
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MAPLE
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select(t -> isprime(t - numtheory:-lambda(t)), [$1..10000]);
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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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