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 A117580 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). 0
 1, 9, 25, 27, 49, 81, 125, 169, 225, 343, 361, 441, 729, 729, 841, 1331, 1369, 1521, 2197, 2025 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS 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. LINKS FORMULA 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] MATHEMATICA 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}] CROSSREFS Cf. A018226. Sequence in context: A319152 A244623 A339127 * A280609 A340238 A020308 Adjacent sequences:  A117577 A117578 A117579 * A117581 A117582 A117583 KEYWORD nonn,uned AUTHOR Roger L. Bagula, Apr 08 2006 STATUS approved

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Last modified May 11 21:35 EDT 2021. Contains 343808 sequences. (Running on oeis4.)