This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A221718 #11 Feb 03 2025 15:48:11 %S A221718 1,2,3,4,6,9,13,19,27,39,55,78,110,156,221,313,443,627,886,1254,1773, %T A221718 2508,3547,5016,7094,10033,14188,20066,28377,40132,56755,80264,113511, %U A221718 160529,227023,321059,454046,642119,908093,1284238,1816186,2568476,3632373,5136952,7264747,10273904,14529495,20547809,29058990,41095618,58117981 %N A221718 Floor(sqrt(3*2^n)). %C A221718 Theorem 3 of Dubickas implies that infinitely many terms of this sequence are divisible by 2 or 3 (and hence infinitely many composites). - _Charles R Greathouse IV_, Feb 04 2016 %D A221718 Artūras Dubickas, Prime and composite integers close to powers of a number, Monatsh. Math. 158:3 (2009), pp. 271-284. %H A221718 N. J. A. Sloane, <a href="/A221718/b221718.txt">Table of n, a(n) for n = 0..200</a> %t A221718 Floor[Sqrt[3*2^Range[0,50]]] (* _Harvey P. Dale_, Feb 03 2025 *) %o A221718 (PARI) a(n)=sqrtint(3<<n) \\ _Charles R Greathouse IV_, Feb 04 2016 %Y A221718 Cf. A007283, A114183. %K A221718 nonn %O A221718 0,2 %A A221718 _N. J. A. Sloane_, Jan 30 2013