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%I #13 Aug 07 2023 03:55:05
%S 0,1,8,27,3,34,89,174,24,127,272,465,81,298,575,918,192,565,1016,1551,
%T 375,946,1613,2382,648,1459,2384,62,1029,2122,3347,263,1536,2953,4520,
%U 566,2187,3970,5921,989,3000,5191,7568,1550,3993,6634,9479,2267,5184,8317
%N a(n) = 2*n^3 - floor(2^(1/3)*n)^3.
%C Is there a simple expression for a nontrivial lower bound for a(n)?
%e a(4) = 2*4^3 - floor(2^(1/3)*4)^3 = 2*64 - 5^3 = 3.
%e a(5) = 2*5^3 - floor(2^(1/3)*5)^3 = 2*125 - 6^3 = 34.
%t Table[2 n^3 - Floor[2^(1/3) n]^3, {n, 0, 60}] (* _Vincenzo Librandi_, May 29 2015
%o (PARI) f(n,e=3,b=2)=n^e*b-floor(sqrtn(b,e)*n)^e
%o (Magma) [2*n^3 - Floor(2^(1/3)*n)^3: n in [0..50]]; // _Vincenzo Librandi_, May 29 2015
%Y Cf. A087056 (analog for squares), A257854, A257855 (4th & 5th power).
%K nonn,easy
%O 0,3
%A _M. F. Hasler_, May 28 2015
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