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 A216144 #26 Nov 08 2016 16:59:37 %S A216144 2,3,6,15,49,174,715,3115,14937,80435,447840,2724104,17442772, %T A216144 114379900,784149082,5708691486,43849291331,342473913400, %U A216144 2803269796342,23620771158595,201815957246322,1793779464521956,16342108667160302,154171144824008980,1518409682511777987 %N A216144 Square root of smallest square greater than the product of first n primes. %C A216144 Known values such that a(n)=A145781(n) are a(n)=2,3,6,15 and 715, i.e. for primes p=2,3,5,7 and 17. %C A216144 (The relation a(n)=A145781(n) means that a(n)(a(n)-1) is a primorial number.) - _M. F. Hasler_, Sep 02 2012, - corrected by _Jonathan Sondow_, Sep 02 2012 %H A216144 C. Aebi and G. Cairns, <a href="http://www.parabola.unsw.edu.au/vol45_no1/vol45_no1_1.pdf">Partitions of primes</a>, Parabola 45, Issue 1 (2009); see the table on p. 5. %F A216144 a(n)=sqrt(A002110(n) + A145781(n)). %F A216144 a(n)=A060797(n)+1. - _M. F. Hasler_, Sep 02 2012 %e A216144 a(2) = sqrt(2*3 + A145781(2))= sqrt(2*3 + 3) = sqrt(9) = 3. %o A216144 (PARI) j=[];for (n=1, 30, p = prod(i=1, n, prime(i)); j=concat(j, floor(sqrt((ceil(sqrt(p))^2))));); j %o A216144 (PARI) A216144(n)=sqrtint(prod(k=1,n,prime(k)))+1 \\ - _M. F. Hasler_, Sep 02 2012 %Y A216144 Cf. A002110, A060797, A145781, A215658, A215659. %K A216144 nonn %O A216144 1,1 %A A216144 _Michel Marcus_, Sep 02 2012