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Search: id:A117580
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| A117580 |
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a cubic quadratic sequence arranged so that the modulo 3 equals one cubic sequence is just ahead of the quadratic sequence ( called here the Maestro sequence). |
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+0
1
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| 1, 9, 25, 27, 49, 81, 125, 169, 225, 343, 361, 441, 729, 729, 841, 1331, 1369, 1521, 2197, 2025
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Arranged so that they are near the Magic numbers ( nuclear shell filling numbers): called Maestro as they have to be conducted like an orcestra to get them to behave this way.
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FORMULA
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g[n_] := (n - Floor[n/3])^3 /; Mod[n, 3] - 1 == 0 g[n_] := (2*n - 1)^2 /; (n < 4) g[n_] := (2*n - 1)^2 /; (n > 13) && (n < 17) g[n_] := (2*n - 3)^2 /; (n > 4) && (n < 13) g[n_] := (2*n + 3)^2 /; (n >= 17) && (n < 19) g[n_] := (2*n + 5)^2 /; (n >= 18) a(n) = g[n]
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MATHEMATICA
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g[n_] := (n - Floor[n/3])^3 /; Mod[n, 3] - 1 == 0 g[n_] := (2*n - 1)^2 /; (n < 4) g[n_] := (2*n - 1)^2 /; (n > 13) && (n < 17) g[n_] := (2*n - 3)^2 /; (n > 4) && (n < 13) g[n_] := (2*n + 3)^2 /; (n >= 17) && (n < 19) g[n_] := (2*n + 5)^2 /; (n >= 18) a=Table[g[n], {n, 1, 20}]
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CROSSREFS
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Cf. A018226.
Sequence in context: A020210 A062739 A075109 this_sequence A020308 A108989 A068583
Adjacent sequences: A117577 A117578 A117579 this_sequence A117581 A117582 A117583
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KEYWORD
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nonn,uned,probation
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Apr 08 2006
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