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A120309
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Numbers k such that pi(k) == 0 (mod 4), where pi() = A000720.
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2
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1, 7, 8, 9, 10, 19, 20, 21, 22, 37, 38, 39, 40, 53, 54, 55, 56, 57, 58, 71, 72, 89, 90, 91, 92, 93, 94, 95, 96, 107, 108, 131, 132, 133, 134, 135, 136, 151, 152, 153, 154, 155, 156, 173, 174, 175, 176, 177, 178, 193, 194, 195, 196
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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a = Flatten[Table[If[Mod[PrimePi[n], 4] == 0, n, {}], {n, 1, 200}]]
Select[Range[200], Mod[PrimePi[#], 4]==0&] (* Harvey P. Dale, Jul 20 2024 *)
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PROG
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(PARI) isok(k) = (primepi(k) % 4) == 0; \\ Michel Marcus, Feb 09 2021
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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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