

A117580


A cubic quadratic sequence arranged so that the modulo3 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
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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

Table of n, a(n) for n=0..19.


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: A319165 A319152 A244623 * A280609 A020308 A108989
Adjacent sequences: A117577 A117578 A117579 * A117581 A117582 A117583


KEYWORD

nonn,uned


AUTHOR

Roger L. Bagula, Apr 08 2006


STATUS

approved



