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A325462
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a(n) is the least number not 2*a(m) or 3*a(m)-1 for any m < n.
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4
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1, 3, 4, 5, 7, 9, 12, 13, 15, 16, 17, 19, 21, 22, 23, 25, 27, 28, 29, 31, 33, 36, 37, 39, 40, 41, 43, 45, 48, 49, 51, 52, 53, 55, 57, 59, 60, 61, 63, 64, 67, 69, 70, 71, 73, 75, 76, 77, 79, 81, 84, 85, 87, 88, 89, 91, 93, 94, 95, 97, 99, 100, 101, 103, 105
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OFFSET
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1,2
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LINKS
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EXAMPLE
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The sequence necessarily starts with 1. The next 2 terms are determined as follows: because a(1) = 1, the number 2 is disallowed, so that a(2) = 3, whence the numbers 6 and 8 are disallowed, and a(3) = 4. See A325417 for a guide to related sequences.
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MATHEMATICA
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a = {1}; Do[AppendTo[a, NestWhile[# + 1 &, Last[a] + 1, Apply[Or,
Map[MemberQ[a, #] &, Select[Flatten[{#/2, (#+1)/3}],
IntegerQ]]] &]], {150}]; a (* A325462 *)
Complement[Range[Last[a]], a] (* A325463 *)
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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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