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A175727
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Numbers k such that both A000203(k)-k-1 and A000203(k)-2*k-1 are prime numbers.
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2
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30, 42, 60, 70, 78, 102, 138, 186, 198, 216, 222, 228, 240, 246, 258, 270, 282, 360, 372, 390, 414, 438, 492, 498, 546, 582, 600, 606, 642, 708, 720, 756, 762, 774, 786, 810, 852, 870, 930, 942, 954, 1002, 1014, 1020, 1026, 1038, 1068, 1086, 1182, 1266, 1290
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OFFSET
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1,1
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COMMENTS
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A simpler version of A179945, added at the request of the editor-in-chief.
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LINKS
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MAPLE
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q:= n-> (t-> andmap(isprime, [t-n-1, t-2*n-1]))(numtheory[sigma](n)):
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PROG
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CROSSREFS
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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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