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Integer part of sqrt(n)+sqrt(n+1)+sqrt(n+2)+sqrt(n+3).
2

%I #18 Sep 08 2022 08:45:23

%S 6,7,8,9,10,10,11,12,12,13,14,14,15,15,16,16,17,17,18,18,18,19,19,20,

%T 20,20,21,21,22,22,22,23,23,23,24,24,24,25,25,25,26,26,26,26,27,27,27,

%U 28,28,28,28,29,29,29,30,30,30,30,31,31,31,31,32,32,32,32,33,33,33,33,34

%N Integer part of sqrt(n)+sqrt(n+1)+sqrt(n+2)+sqrt(n+3).

%H X. Zhan, <a href="http://dx.doi.org/10.1007/BF02985850">Formulae for sums of consecutive square roots</a>, The Math. Intelligencer, 27, No. 4, 2005, 4-5.

%F a(n) = floor(sqrt(16n+20)).

%p seq(floor(sqrt(16*n+20)),n=1..90);

%t Table[Floor[Sqrt[16 n + 20]], {n, 80}] (* _Vincenzo Librandi_, Jun 28 2015 *)

%o (PARI) vector(80, n, sqrtint(16*n+20)) \\ _Michel Marcus_, Jun 27 2015

%o (Magma) [Floor(Sqrt(16*n+20)): n in [1..80]]; // _Vincenzo Librandi_, Jun 28 2015

%Y Cf. A000267, A114458, A114460.

%K nonn

%O 1,1

%A _Emeric Deutsch_, Nov 28 2005