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A231966
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Squarefree numbers (from A005117) with prime divisors in a 2p+1 progression.
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4
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10, 21, 55, 110, 253, 1081, 1265, 1711, 2530, 3403, 5671, 11891, 13861, 15931, 25651, 34453, 59455, 60031, 64261, 73153, 108811, 114481, 118910, 126253, 158203, 171991, 258121, 351541, 371953, 392941, 482653, 518671, 568301, 703891, 822403, 853471, 869221, 933661
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OFFSET
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1,1
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COMMENTS
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Squarefree numbers with k>=2 prime divisors of the form p_1 * p_2 * … * p_k, where p_1 < p_2 < … < p_k = primes with p_k = 2 * p_(k-1) + 1.
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LINKS
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EXAMPLE
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118910 = 2*5*11*23*47, where 5 = 2*2 + 1, 11 = 2*5 + 1, 23 = 2*11 + 1, 47 = 2*23 + 1.
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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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