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A326583
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Integers k >= 0 such that 2*k + 1 is prime or square.
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1
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0, 1, 2, 3, 4, 5, 6, 8, 9, 11, 12, 14, 15, 18, 20, 21, 23, 24, 26, 29, 30, 33, 35, 36, 39, 40, 41, 44, 48, 50, 51, 53, 54, 56, 60, 63, 65, 68, 69, 74, 75, 78, 81, 83, 84, 86, 89, 90, 95, 96, 98, 99, 105, 111, 112, 113, 114, 116, 119, 120
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OFFSET
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1,3
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LINKS
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MAPLE
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s := n -> if irem(n, 2) = 1 and (isprime(n) or issqr(n)) then (n-1)/2 else NULL fi:
seq(s(n), n=0..241);
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MATHEMATICA
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Select[Range[0, 120], Or[IntegerQ@ Sqrt@ #, PrimeQ@ #] &[2 # + 1] &] (* Michael De Vlieger, Jul 15 2019 *)
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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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