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 A104055 Number of numbers 0 <= i <= n such that i is a square or a cube (or both). 1
 1, 2, 2, 2, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Sixth powers are counted only once (0 and 1 are both squares and cubes, for example, but they are not counted twice). LINKS FORMULA a(n) = 1 + floor(n^(1/2)) + floor(n^(1/3)) - floor(n^(1/6)). - N. J. A. Sloane, Mar 16 2005 EXAMPLE a(9)=5 because we have 0,1,4,8 and 9. MAPLE seq(1+floor(evalf(n^(1/2)))+floor(evalf(n^(1/3)))-floor(evalf(n^(1/6))), n=0..94); # Emeric Deutsch MATHEMATICA Rest[Accumulate[Table[Which[IntegerQ[Sqrt[n]], 1, IntegerQ[Surd[n, 3]], 1, True, 0], {n, 0, 150}]]] (* Harvey P. Dale, Jun 24 2017 *) PROG (PARI) a(n)=sqrtint(n)+sqrtnint(n, 3)-sqrtnint(n, 6) \\ Charles R Greathouse IV, Jun 25 2017 CROSSREFS Cf. A104058. Sequence in context: A189575 A216503 A216672 * A216200 A157873 A022870 Adjacent sequences:  A104052 A104053 A104054 * A104056 A104057 A104058 KEYWORD easy,nonn AUTHOR Giovanni Teofilatto, Mar 02 2005 EXTENSIONS More terms from Emeric Deutsch, Mar 24 2005 Corrected by Harvey P. Dale, Jun 24 2017 Definition revised by N. J. A. Sloane, Jun 25 2017 STATUS approved

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Last modified September 21 19:59 EDT 2019. Contains 327282 sequences. (Running on oeis4.)