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A237989
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Numbers m such that the numbers of primes, even positive integers and odd positive integers less than or equal to m are all odd.
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2
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2, 6, 18, 26, 34, 42, 50, 70, 74, 78, 86, 98, 106, 110, 130, 138, 150, 158, 162, 170, 198, 214, 218, 222, 234, 238, 242, 246, 250, 258, 262, 270, 278, 286, 290, 310, 314, 334, 354, 358, 370, 382, 390, 394, 402, 406, 442, 450, 454, 462, 470, 474, 478, 490, 502
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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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EXAMPLE
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A cubic die whose faces are marked with the numbers from 1 to 6 has odd number of sides marked with prime numbers (2, 3 and 5), even integers (2, 4 and 6) and odd integers (1, 3 and 5). Therefore, 6 is in the sequence.
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PROG
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(PARI) isok(n) = (primepi(n) % 2) && ((n % 4) == 2); \\ Michel Marcus, Mar 12 2014
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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