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A098972
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a(0) = 1; for n > 0, a(n) = 2*a(floor(n/2)) + 3*a(floor(n/3)).
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1
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1, 5, 13, 25, 41, 41, 89, 89, 121, 157, 157, 157, 301, 301, 301, 301, 365, 365, 581, 581, 581, 581, 581, 581, 965, 965, 965, 1073, 1073, 1073, 1073, 1073, 1201, 1201, 1201, 1201, 2065, 2065, 2065, 2065, 2065, 2065, 2065, 2065, 2065, 2065, 2065, 2065, 3025
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OFFSET
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0,2
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COMMENTS
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a(n) > a(n-1) iff n is a 3-smooth number.
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LINKS
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FORMULA
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MATHEMATICA
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a[0] = 1; a[n_] := a[n] = 2*a[Floor[n/2]] + 3*a[Floor[n/3]]; Array[a, 50, 0] (* Amiram Eldar, Jul 13 2023 *)
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PROG
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(PARI) a(n)=if(n<1, 1, a(floor(n/2))*2+3*a(floor(n/3)))
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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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