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 A056604 #43 Sep 08 2022 08:45:01
%S A056604 1,2,6,60,420,27720,360360,12252240,232792560,5354228880,
%T A056604 2329089562800,72201776446800,5342931457063200,219060189739591200,
%U A056604 9419588158802421600,442720643463713815200,164249358725037825439200,9690712164777231700912800,591133442051411133755680800
%N A056604 a(0)=1; thereafter a(n) = lcm(1, 2, 3, 4, ..., prime(n)).
%C A056604 Previous name was: Values of lcm[1,...,m], m = prime, whose squarefree kernels give A002110.
%C A056604 a(n) can be used like A006939(n) for certain kinds of rounding. E.g., the Babylonian a(3) = 60 = 2*2*3*5 divides A006939(3) = 360 = 2*2*2*3*3*5. - _Frank Ellermann_, Dec 18 2001
%C A056604 a(342) has 1000 decimal digits. - _Michael De Vlieger_, Mar 05 2017
%H A056604 Michael De Vlieger, <a href="/A056604/b056604.txt">Table of n, a(n) for n = 0..342</a>
%F A056604 a(n) = prime(n)^r(n) *...* prime(1)^r(1) for maximal prime(j)^r(j) <= prime(n).
%F A056604 a(n) = Product_{k=1..n} prime(k)^floor(log(prime(n))/log(prime(k))). - _Daniel Suteu_, Oct 09 2017
%F A056604 a(n) = A003418(prime(n)). - _M. F. Hasler_, Jan 04 2020
%e A056604 a(5) = lcm(1,2,...,10,11) = 27720, prime(5) = 11. Not all possible lcm(1,..,n) values of A003418 occur, e.g., 12, 840, 25520, etc. are not present. Their squarefree kernels gives exactly A002110.
%p A056604 a:= n-> ilcm(`if`(n=0, NULL, $1..ithprime(n))):
%p A056604 seq(a(n), n=0..20); # _Alois P. Heinz_, Dec 05 2014
%t A056604 Table[If[n == 0, 1, LCM @@ Range@ Prime@ n], {n, 0, 18}] (* _Michael De Vlieger_, Mar 05 2017 *)
%o A056604 (PARI) a(n)=lcm(vector(prime(n),i,i)) \\ _Charles R Greathouse IV_, Oct 27 2013
%o A056604 (PARI) apply( A056604(n)=lcm([2..if(n,prime(n))]), [0..20]) \\ Or A056604(n) = A003418(prime(n)), might be more efficient. - _M. F. Hasler_, Jan 04 2020
%o A056604 (Magma) [1] cat [Lcm([2..p]): p in PrimesUpTo(65)]; // _Bruno Berselli_, Feb 08 2015
%Y A056604 Cf. A002110, A003418, A006939, A034386, A051451.
%K A056604 nonn
%O A056604 0,2
%A A056604 _Labos Elemer_, Aug 07 2000
%E A056604 a(16) from _Frank Ellermann_, Dec 18 2001
%E A056604 New name from _Charles R Greathouse IV_, Oct 27 2013
%E A056604 More terms from _Alois P. Heinz_, Dec 05 2014
%E A056604 a(0)=1 added to definition by _N. J. A. Sloane_, Jan 05 2020