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a(n) = ceiling((n - sqrt(n))^n).
1

%I #14 Dec 04 2017 02:55:01

%S 1,0,1,3,16,162,2004,29676,511660,10077696,223416176,5508996067,

%T 149620408779,4439426853025,142915981606747,4962277770372786,

%U 184884258895036416,7358499526831141011,311624392527600238320,13992684008957401915051,664101403687644955591709

%N a(n) = ceiling((n - sqrt(n))^n).

%C Suggested by the discovery of Boris Alexeev in the year 2004 that a(6) = 2004.

%H Robert Israel, <a href="/A091146/b091146.txt">Table of n, a(n) for n = 0..389</a>

%p f:= n -> ceil((n-sqrt(n))^n):

%p map(f, [$0..40]); # _Robert Israel_, Dec 03 2017

%t Join[{1},Table[Ceiling[(n-Sqrt[n])^n],{n,20}]] (* _Harvey P. Dale_, Jun 19 2016 *)

%o (PARI) a(n) = ceil((n - sqrt(n))^n); \\ _Altug Alkan_, Dec 04 2017

%K nonn

%O 0,4

%A _N. J. A. Sloane_, Feb 23 2004